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REVIEW 4 major objections 3 minor 76 references

Stopping cross-section for protons across different phases of water

T0 review · 4 major / 3 minor · reviewed 2026-08-07 · deepseek-v4-flash

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Pith's one-line read Protons lose energy at the same rate in liquid water and amorphous ice over the full 0.001–10 MeV range, making amorphous ice a viable surrogate for liquid-water stopping measurements.

desk verdict A useful, well-executed application of the TDDFT-Penn method to water phases; the liquid–amorphous identity is plausible and practically important, but it relies on an unvalidated finite-q assumption and lacks uncertainty quantification. read the letter →

arxiv 2505.23396 v2 pith:L77S5XNH submitted 2025-05-29 physics.med-ph

F. Matias , N. E. Koval , P. de Vera , R. Garcia-Molina , I. Abril , J. M. B. Shorto , H. Yoriyaz , J. J. N. Pereira
show 4 more authors
T. F. Silva M. H. Tabacniks M. Vos P. L. Grande
This is my paper
classification physics.med-ph PACS 34.50.Bw87.55.-x71.15.Mb
keywords stoppingpowerprotontherapyliquidwateramorphousicetime-dependentdensityfunctionaltheoryPennmethodenergy-lossfunctionphaseeffectsin
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

Proton therapy requires accurate values of how fast protons shed energy in liquid water, but those values are the hardest to measure because liquid water is volatile and difficult to use in transmission experiments. The authors compute the electronic stopping cross section for protons in water vapor, hexagonal ice, amorphous ice, and liquid water over 0.001–10 MeV using a hybrid real-time time-dependent density functional theory (TDDFT) plus Penn method. Their central result is that the stopping cross section of liquid water and amorphous ice is practically identical over the entire energy range, mirroring the recent observation for low-energy electrons and suggesting the equivalence holds for all charged particles. If correct, amorphous ice could be used in experiments to determine the biologically relevant liquid-water stopping power that fixes the Bragg peak position in treatment planning.

What carries the argument

The load-bearing object is the TDDFT-Penn stopping cross section, Eq. (5) of the paper: a weighted integral over jellium stopping powers, $[dE/dz(v)] = \int d\omega_p\, g(\omega_p)\,[dE/dz(v,\omega_p)]_{\text{TDDFT}}$, with $g(\omega_p) = (2/\pi\omega_p)\,\text{ELF}(\omega_p)$ taken from the optical energy-loss function of each water phase. Real-time TDDFT supplies, for each jellium density, the full non-perturbative stopping of a proton crossing the sphere, including all momentum-transfer physics; the Penn weight then encodes the phase-specific electronic structure through the optical ELF, respecting the $f$-sum rule and reproducing the Bethe limit at high energies. This combination is what lets the method stay accurate below the stopping maximum, where perturbative dielectric formalisms fail, and it is what produces the near-identical liquid and amorphous curves.

What would settle it

A direct measurement of proton energy loss through thin amorphous-ice films and thin liquid-water jets over roughly 0.01–1 MeV, compared at identical proton velocities, would settle the central claim: a difference between the two stopping cross sections larger than the few-percent residual the model predicts near the maximum would falsify it. An alternative is an atomistic real-time TDDFT simulation of explicit liquid water and amorphous ice configurations at low proton energies, which would test the equivalence without the jellium-Penn mixing.

Watch

Extended reading notes

Core claim

The paper's central discovery is that protons are stopped at essentially the same rate by liquid water and amorphous ice throughout the energy range from 0.001 to 10 MeV, even though the two phases have visibly different optical energy-loss spectra. The authors reach this by computing the electronic stopping cross section with the TDDFT-Penn approach, which replaces explicit atomistic simulations with real-time TDDFT on jellium spheres and weights the results by the phase-specific optical energy-loss function. The calculation reproduces existing experiments for vapor and ice, and it agrees with an independent dielectric-response calculation in the 0.2–2 MeV window, supporting the suggestion that earlier Monte-Carlo-derived liquid-water measurements underestimated the stopping power near the maximum. The liquid/amorphous identity is presented as a generalization of a previously reported electron result, implying the equivalence is a property of the water target rather than of any particular projectile.

Load-bearing premise

The whole calculation assumes that a real material's stopping power can be built from jellium stopping powers weighted only by its optical energy-loss function, with all finite-momentum behavior supplied intrinsically by the TDDFT electron gas; if liquid water and amorphous ice differ at low energies in a way not visible in their optical spectra, the near-identical result could be an artifact of that model.

Editorial extensions

If this is right

  • Amorphous ice becomes a practical experimental surrogate for liquid water in proton stopping measurements, bypassing the volatility problem.
  • Proton therapy treatment-planning codes can use ice-derived stopping data with confidence that they reflect liquid-water behavior down to the sub-MeV range.
  • The equivalence strengthens the idea that the electron and proton identity is universal for charged particles, so the same surrogate logic may apply to alpha particles and heavier ions.
  • The calculation indicates that certain experimental liquid-water stopping values derived from Monte Carlo fitting underestimate the true stopping power around its maximum, in line with earlier critical re-analyses.
  • Phase differences between vapor and condensed water are captured correctly, reinforcing that the number of effective screening electrons per molecule, not just mass density, controls low-energy stopping.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • If the equivalence holds for all charged particles, it likely extends to heavier ions used in hadron therapy, such as carbon, so amorphous ice could supply stopping data across the ion therapy spectrum without new liquid-water experiments.
  • The TDDFT-Penn method's blend of speed and non-perturbative accuracy suggests it could become a general tool for generating stopping-power tables for other biological and astrochemical materials where experiments are sparse.
  • A crisp test of the model's assumption would be inelastic X-ray scattering measurements of the energy-loss function at finite momentum transfer for liquid water and amorphous ice; if the two diverge away from the optical limit, the predicted identity could be a model artifact.
  • The identity should be checked against nuclear stopping and channeling effects at the lowest energies, where the projectile's trajectory and the discrete molecular structure of amorphous ice could matter more than the homogeneous jellium picture.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

4 major / 3 minor

Summary. The paper proposes a hybrid method, TDDFT-Penn, that combines real-time time-dependent density functional theory (TDDFT) for a jellium sphere with the Penn weighting scheme built from the optical energy-loss function (ELF) of the target. The method is applied to compute proton stopping cross-sections (SCS) for water vapor, amorphous ice, hexagonal ice, and liquid water over 0.001-10 MeV. The authors report good agreement with experimental data for vapor and amorphous ice and with MELF-GOS calculations for liquid water above ~0.2 MeV. The central claim is that the SCS of liquid water and amorphous ice are practically identical over the whole energy range, which would allow amorphous ice to serve as a surrogate for liquid water in stopping-power measurements relevant to proton therapy and astrochemistry.

Significance. If the central claim is correct, the paper provides a computationally efficient and non-perturbative route to stopping powers below the Bragg-peak maximum, a regime where existing models and experiments are uncertain. The method's ability to reproduce vapor and ice data with a single framework is a genuine strength, and the paper makes the potentially important observation that the liquid-amorphous identity previously reported for low-energy electrons may extend to protons. The comparison with multiple experimental datasets and the transparent derivation of the Penn weighting from optical ELFs are also strengths. However, the surrogate conclusion rests on an assumption about finite-momentum-transfer physics that is not independently validated, and the claimed identity is not yet quantitatively secured.

major comments (4)
  1. [Eq. (5) and Fig. 3(b)] The central claim that liquid water and amorphous ice have 'practically identical' SCS follows almost directly from the similarity of their optical ELFs and the assumption in Eq. (5) that all finite-momentum-transfer physics is supplied by the jellium TDDFT calculation. The paper asserts that momentum transfers are implicitly accounted for in the TDDFT simulations, but the jellium is a homogeneous electron gas; it cannot encode phase-specific molecular excitations, band gaps, or intermolecular correlations that control the real q-dependence of the water response. No test of the q-dispersion of the ELF or a comparison with an independent calculation that includes phase-specific finite-q effects is provided. The surrogate claim is therefore not yet secured; it is a model prediction that needs validation against a calculation or measurement that does not share the same k=0-only input.
  2. [Fig. 3 and Supplemental Material, jellium parameters] The calculated SCS curves are presented without error bars or uncertainty quantification. The input optical ELFs are fits to experimental data (with inherent uncertainties), and the TDDFT results depend on the choice of jellium sphere size (Ne=588) and the central-trajectory protocol. A sensitivity analysis varying Ne and the ELF fit parameters is necessary to establish whether the apparent liquid-amorphous identity in Fig. 3(b) is robust or reflects a small difference that is within the model's uncertainty. Without such an analysis, the claim of 'practical identity' is not quantitatively supported.
  3. [Supplemental Material, Section 'Details on the TDDFT-Penn methodology'] The jellium sphere size (Ne=588) and the central-trajectory-only protocol are adopted without convergence tests. The paper does not demonstrate that the computed energy loss has converged with respect to cluster radius for the relevant plasmon frequencies (rs from 0.6 to 5.0 a.u.), nor that an impact-parameter average is unnecessary. At low proton energies (≤0.2 MeV), where the stopping maximum lies and the TDDFT results are most sensitive to the details of the electron dynamics, finite-cluster boundary effects could be significant. This is a load-bearing gap for the claimed accuracy below the stopping maximum.
  4. [Fig. 3(a) and surrounding text] The validation of the liquid-water results in the 0.2-4 MeV range relies on agreement with MELF-GOS, but MELF-GOS uses the same optical ELF as input and a chosen dispersion scheme; it is not an independent check of the finite-momentum-transfer assumption. The atomistic TDDFT calculations shown in Fig. 3(a) disagree with the present results below ~0.2 MeV, and no direct experimental data for liquid water exist in that range. The paper should either provide a new validation (e.g., against re-analyzed Shimizu et al. data, or an independent first-principles calculation that treats the full phase-specific response) or clearly frame the liquid-amorphous identity and the low-energy predictions as model-based extrapolations.
minor comments (3)
  1. [Abstract and Section 1] The phrase 'practically identical' is used without a quantitative criterion. Define a tolerance (e.g., a maximum relative difference over a stated energy range) that constitutes 'practical identity' so that the claim is falsifiable.
  2. [Fig. 1 and text] In the sum-rule discussion, the numbers '2.0 electrons', '1.1 electrons', and '1.2 electrons' appear in the figure but are not clearly associated with the phases in the text; label the figure entries or describe them in the caption.
  3. [Reference list] Reference [28] (Signorell) is cited as the electron-result analogue, but the paper does not discuss the differences between electron and proton scattering mechanisms that might affect the transferability of the liquid-amorphous identity; a short discussion would help the reader assess the 'all charged particles' extrapolation.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: liquid/amorphous SCS identity is a forward-model output from independent optical ELFs.

full rationale

The derivation chain is self-contained and no circular step can be exhibited. The central result, that liquid water and amorphous ice have practically identical proton SCS, is obtained by applying the same TDDFT jellium kernel [dE/dz(v,omega_p)] to two different empirical optical ELFs (Hayashi et al. for liquid, Daniels for amorphous) through Eq. (5). The kernel is phase-independent and computed from first principles; the phase distinction enters only through the measured ELF, which is an external input. Nothing is fitted to the target SCS values: the Mermin parameters fit the optical ELFs in the optical limit, not the stopping data, and the resulting SCS curves are then compared with independent experimental SCS data for vapor, amorphous ice, and liquid water. The liquid/amorphous identity is therefore a model prediction, not a restatement of the inputs. The agreement with MELF-GOS is a consistency check using the same optical ELF inputs and is not independent validation of the finite-momentum-transfer dispersion, but this is a validation limitation, not circularity. Self-citations such as Ref. [46] document the prior development of the TDDFT-Penn method, whose equations are re-derived in the main text and Supplemental Material; they do not carry the central claim alone. There is no imported uniqueness theorem and no ansatz smuggled in by citation beyond the explicitly stated Penn weighting, which is standard and parameter-free once the ELF is given. The lack of convergence tests for jellium sphere size and trajectory is a real scientific gap, but it does not make the prediction equivalent to its inputs. Score 0.

Assumptions & free parameters 3 free parameters · 5 assumptions · 0 invented entities

The central claim rests on the Penn decomposition, the sufficiency of the optical ELF, the ALDA approximation, the jellium cluster convergence, and the accuracy of the literature ELFs. The MELF-GOS fits and the assumed phase densities are free parameters that directly affect the SCS curves.

free parameters (3)
  • MELF-GOS fit parameters for each water phase optical ELF = not listed in paper
    The optical ELFs for liquid, amorphous, hexagonal, and vapor phases are fitted to experimental data using Mermin-type loss functions and hydrogenic GOS; these fitted amplitudes, energies, and widths determine the Penn weighting g(ωp) in Eq. (2).
  • Jellium cluster electron number Ne = 588
    The number of electrons in the jellium spheres is set to Ne=588 (closed shell) as a numerical setup; results are assumed converged with respect to cluster size.
  • Phase mass densities used for SCS normalization = 1.0 (liquid), 0.94 (amorphous and hexagonal), 0.125 (vapor) g/cm3
    The stopping cross section is obtained by dividing the ESP by the assumed mass density of each phase; the comparison between phases depends on these literature values.
assumptions (5)
  • domain assumption Penn model: the stopping power of a real material equals the weighted average of jellium stopping powers, with weights from the optical ELF (Eqs. (1)-(2)).
    The entire TDDFT-Penn method rests on this decomposition; the paper does not prove it for low-energy protons in water.
  • domain assumption Optical ELF (k=0) is sufficient; momentum transfer dispersion is implicitly captured by the TDDFT jellium response.
    The paper states that 'the momentum transfers are implicitly accounted for in the TDDFT simulations', but no direct validation of this equivalence is provided.
  • domain assumption Exchange-correlation is treated in the adiabatic local density approximation (ALDA) with the Gunnarsson-Lundqvist kernel.
    The real-time TDDFT simulations use ALDA; this approximation may affect low-energy stopping where dynamic correlation matters.
  • domain assumption The jellium sphere with Ne=588 electrons and the proton traversing through its center gives a converged, representative stopping value for the bulk phase.
    No convergence study with respect to Ne or trajectory impact parameter is shown in the main text.
  • domain assumption The ELFs from Hayashi et al. (liquid), Daniels (amorphous), Kobayashi (hexagonal), and Chan et al. (vapor) are accurate measurements of the optical response of each phase.
    The identity of liquid and amorphous ice SCS could be an artifact if the two experimental ELFs, measured by different techniques, are not directly comparable.

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Cite this review

Pith. "Pith review of Stopping cross-section for protons across different phases of water." pith.science (2026). https://pith.science/paper/L77S5XNH

@misc{pith2026250523396,
  author       = {Pith},
  title        = {Pith review of: Stopping cross-section for protons across different phases of water},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/L77S5XNH}},
  note         = {Machine review of arXiv:2505.23396}
}
read the original abstract

Accurately quantifying the energy loss rate of proton beams in liquid water is crucial for the precise application and improvement of proton therapy, whereas the slowing down of proton in water ices also plays an important role in astrophysics. However, precisely determining the electronic stopping power, particularly for the liquid phase, has been elusive so far. Experimental techniques are difficult to apply to volatile liquids, and the availability of sufficient reliable measurements has been limited to the solid and vapor phases. The accuracy of current models is typically limited to proton energies just above the energy-loss maximum, making it difficult to predict radiation effects at an energy range of special relevance. We elucidate the phase differences in proton energy loss in water in a wide energy range (0.001-10 MeV) by means of real-time time-dependent density functional theory combined with the Penn method. This non-perturbative model, more computationally-efficient than current approaches, describes the phase effects in water in excellent agreement with available experimental data, revealing clear deviations around the maximum of the stopping power curve and below. As an important outcome, our calculations reveal that proton stopping quantities of liquid water and amorphous ice are identical, in agreement with recent similar observations for low-energy electrons, pointing out to this equivalence for all charged particles. This could help to overcome the limitation in obtaining reliable experimental information for the biologically-relevant liquid water target.

Figures

Figures reproduced from arXiv: 2505.23396 by the authors.

Figure 1
Figure 1. FIG. 1. Energy-loss functions for liquid water [51], amorphous [PITH_FULL_IMAGE:figures/full_fig_p003_1.png] view at source ↗
Figure 3
Figure 3. FIG. 3. (a) SCS of liquid water for protons. TDDFT-Penn [PITH_FULL_IMAGE:figures/full_fig_p004_3.png] view at source ↗

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Works this paper leans on

76 extracted references · 74 canonical work pages

  1. [1]

    Durante and H

    M. Durante and H. Paganetti, Nuclear physics in particle therapy: a review, Reports on Progress in Physics 79, 096702 (2016)

    work page 2016

  2. [2]

    Schardt, T

    D. Schardt, T. Els¨ asser, and D. Schulz-Ertner, Heavy- ion tumor therapy: Physical and radiobiological benefits, Reviews of Modern Physics 82, 383 (2010)

    work page 2010

  3. [3]

    Andreo, On the clinical spatial resolution achievable with protons and heavier charged particle radiotherapy beams, Physics in Medicine and Biology 54, N205 (2009)

    P. Andreo, On the clinical spatial resolution achievable with protons and heavier charged particle radiotherapy beams, Physics in Medicine and Biology 54, N205 (2009)

    work page 2009

  4. [4]

    Paul, On the accuracy of stopping power codes and ion ranges used for hadron therapy, Advances in Quantum Chemistry 65, 39 (2013)

    H. Paul, On the accuracy of stopping power codes and ion ranges used for hadron therapy, Advances in Quantum Chemistry 65, 39 (2013)

    work page 2013

  5. [5]

    Nikjoo, S

    H. Nikjoo, S. Uehara, and D. Emfietzoglou, Interaction of Radiation with Matter (CRC Press, Boca Raton, FL, USA, 2012)

    work page 2012

  6. [6]

    Nikjoo, D

    H. Nikjoo, D. Emfietzoglou, T. Liamsuwan, R. Taleei, D. Liljequist, and S. Uehara, Radiation track, DNA damage and response—a review, Reports on Progress in Physics 79, 116601 (2016)

    work page 2016

  7. [7]

    R. A. Baragiola, Water ice on outer solar system sur- faces: Basic properties and radiation effects, Planetary and Space Science 51, 953 (2003)

    work page 2003

  8. [8]

    L. S. Farenzena, P. Iza, R. Martinez, F. A. Fernandez- Lima, E. S. Duarte, G. S. Faraudo, C. R. Ponciano, M. G. P. Homem, A. N. de Brito, K. Wien, and E. F. da Silveira, Electronic Sputtering Analysis of Astrophys- ical Ices, Earth, Moon, and Planets 97, 311 (2005)

    work page 2005

Show all 76 references
  1. [9]

    L. I. Cleeves, E. A. Bergin, C. M. O. Alexander, F. Du, D. Graninger, K. I. ¨Oberg, and T. J. Harries, The ancient heritage of water ice in the solar system, Science 345, 1590 (2014)

    2014

  2. [10]

    Dartois, J

    E. Dartois, J. A. Noble, P. Caselli, H. J. Fraser, I. Jim´ enez-Serra, B. Mat´ e, M. K. McClure, G. J. Melnick, Y. J. Pendleton, T. Shimonishi, Z. L. Smith, J. A. Sturm, A. Taillard, V. Wakelam, A. C. A. Boogert, M. N. Droz- dovskaya, J. Erkal, D. Harsono, V. J. Herrero, S. Io...

    2024

  3. [11]

    Protopapa, U

    S. Protopapa, U. Raut, I. Wong, J. Stansberry, G. L. Vil- lanueva, J. Cook, B. Holler, W. M. Grundy, R. Brunetto, R. J. Cartwright, B. Mamo, J. P. Emery, A. H. Parker, A. Guilbert-Lepoutre, N. Pinilla-Alonso, S. N. Milam, and H. B. Hammel, Detection of carbon dioxide and hy- d...

    2024

  4. [12]

    J. M. Sunshine, M. F. A’Hearn, O. Groussin, J.-Y. Li, M. J. S. Belton, W. A. Delamere, J. Kissel, K. P. Klaasen, L. A. McFadden, K. J. Meech, H. J. Melosh, P. H. Schultz, P. C. Thomas, J. Veverka, D. K. Yeomans, I. C. Busko, M. Desnoyer, T. L. Farnham, L. M. Feaga, D. L. Hampt...

    2006

  5. [13]

    B. D. Teolis, C. Plainaki, T. A. Cassidy, and U. Raut, Water ice radiolytic o2, h2, and h2o2 yields for any pro- jectile species, energy, or temperature: A model for icy astrophysical bodies, Journal of Geophysical Research: Planets 122, 1996 (2017)

    2017

  6. [14]

    R. A. Baragiola, M. J. Loeffler, U. Raut, R. A. Vidal, and C. D. Wilson, Laboratory studies of radiation effects in water ice in the outer solar system, Radiation Physics and Chemistry 72, 187 (2005), christiane Ferradini Memorial Issue

    2005

  7. [15]

    Jenniskens and D

    P. Jenniskens and D. F. Blake, Structural transitions in amorphous water ice and astrophysical implications, Sci- ence 265, 753 (1994)

    1994

  8. [16]

    Mej ´ ıa, C., de Barros, A. L. F., Domaracka, A., Boduch, P., Rothard, H., and da Silveira, E. F., Modifications of astrophysical ices induced by cosmic rays - i. water, carbon monoxide, and methanol mixtures, Astronomy & 6 Astrophysics 687, A227 (2024)

    2024

  9. [17]

    N. F. W. Ligterink, P. Pinilla, N. van der Marel, J. T. van Scheltinga, A. S. Booth, C. M. O. Alexander, and M. E. I. Riebe, The rapid formation of macromolecules in irradiated ice of protoplanetary disk dust traps, Nature Astronomy 8, 1257 (2024)

    2024

  10. [18]

    Shimizu, M

    M. Shimizu, M. Kaneda, T. Hayakawa, H. Tsuchida, and A. Itoh, Stopping cross sections of liquid water for MeV energy protons, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 267, 2667 (2009)

    2009

  11. [19]

    Shimizu, T

    M. Shimizu, T. Hayakawa, M. Kaneda, H. Tsuchida, and A. Itoh, Stopping cross-sections of liquid water for 0.3–2.0 MeV protons, Vacuum 84, 1002 (2010)

    2010

  12. [20]

    Siiskonen, H

    T. Siiskonen, H. Kettunen, K. Per¨ aj¨ arvi, A. Javanainen, M. Rossi, W. H. Trzaska, J. Turunen, and A. Virta- nen, Energy loss measurement of protons in liquid water, Physics in Medicine & Biology 56, 2367 (2011)

    2011

  13. [21]

    Garcia-Molina, I

    R. Garcia-Molina, I. Abril, P. de Vera, and H. Paul, Com- ments on recent measurements of the stopping power of liquid water, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Ma- terials and Atoms 299, 51 (2013)

    2013

  14. [22]

    de Vera, R

    P. de Vera, R. Garcia-Molina, and I. Abril, Simulation of the energy spectra of swift light ion beams after travers- ing cylindrical targets: a consistent interpretation of ex- perimental data relevant for hadron therapy, European Physical Journal D 73, 209 (2019)

    2019

  15. [23]

    Bauer, W

    P. Bauer, W. K¨ aferb¨ ock, and V. Neˇ cas, Investigation of the electronic energy loss of hydrogen ions in H 2O: in- fluence of the state of aggregation, Nuclear Instruments and Methods in Physics Research Section B: Beam In- teractions with Materials and Atoms 93, 132 (1994)

    1994

  16. [24]

    J. A. Phillips, The Energy Loss of Low Energy Protons in Some Gases, Phys. Rev. 90, 532 (1953)

    1953

  17. [25]

    H. K. Reynolds, D. N. F. Dunbar, W. A. Wenzel, and W. Whaling, The Stopping Cross Section of Gases for Protons, 30-600 keV, Phys. Rev. 92, 742 (1953)

    1953

  18. [26]

    Mitterschiffthaler and P

    C. Mitterschiffthaler and P. Bauer, Stopping cross section of water vapor for hydrogen ions, Nuclear Instruments and Methods in Physics Research Section B: Beam In- teractions with Materials and Atoms 48, 58 (1990)

    1990

  19. [27]

    W. Y. Baek, B. Grosswendt, and G. Willems, Ioniza- tion ranges of protons in water vapour in the energy range 1–100 keV, Radiation Protection Dosimetry 122, 32 (2006)

    2006

  20. [28]

    Signorell, Electron Scattering in Liquid Water and Amorphous Ice: A Striking Resemblance, Physical Re- view Letters 124, 205501 (2020)

    R. Signorell, Electron Scattering in Liquid Water and Amorphous Ice: A Striking Resemblance, Physical Re- view Letters 124, 205501 (2020)

    2020

  21. [29]

    D. R. Penn, Electron mean-free-path calculations using a model dielectric function, Phys. Rev. B 35(2), 482 (1987)

    1987

  22. [30]

    Garcia-Molina, I

    R. Garcia-Molina, I. Abril, I. Kyriakou, and D. Emfiet- zoglou, Energy Loss of Swift Protons in Liquid Water: Role of Optical Data Input and Extension Algorithms, in Radiation Damage in Biomolecular Systems , edited by G. Garc ´ ıa G´ omez-Tejedor and M. C. Fuss (Springer Sci- ...

    2012

  23. [31]

    Vos and P

    M. Vos and P. L. Grande, Extension schemes of the di- electric function, and their implications for ion stopping calculations, Journal of Physics and Chemistry of Solids 133, 187 (2019)

    2019

  24. [32]

    de Vera, I

    P. de Vera, I. Abril, and R. Garcia-Molina, Electronic cross section, stopping power and energy-loss straggling of metals for swift protons, alpha particles and electrons, Frontiers in Materials 10, 1249517 (2023)

    2023

  25. [33]

    K. G. Reeves, Y. Yao, and Y. Kanai, Electronic stopping power in liquid water for protons and α particles from first principles, Phys. Rev. B 94, 041108 (2016)

    2016

  26. [34]

    Y. Yao, D. C. Yost, and Y. Kanai, K-shell core-electron excitations in electronic stopping of protons in water from first principles, Phys. Rev. Lett. 123, 066401 (2019)

    2019

  27. [35]

    B. Gu, B. Cunningham, D. M. Santiburcio, F. D. Pieve, E. Artacho, and J. Kohanoff, Efficient ab initio calcu- lation of electronic stopping in disordered systems via geometry pre-sampling: Application to liquid water, J. Chem. Phys. 153(3), 034113 (2020)

    2020

  28. [36]

    Taioli, P

    S. Taioli, P. E. Trevisanutto, P. de Vera, S. Simonucci, I. Abril, R. Garcia-Molina, and M. Dapor, Relative role of physical mechanisms on complex biodamage induced by carbon irradiation, The Journal of Physical Chemistry Letters 12, 487 (2021)

    2021

  29. [37]

    N. E. Koval, P. Koval, F. Da Pieve, J. Kohanoff, E. Ar- tacho, and D. Emfietzoglou, Inelastic scattering of elec- trons in water from first principles: cross sections and inelastic mean free path for use in monte carlo track- structure simulations of biological damage, Royal Soci...

    2022

  30. [38]

    B. Gu, D. Mu˜ noz-Santiburcio, F. Da Pieve, F. Cleri, E. Artacho, and J. Kohanoff, Bragg’s additivity rule and core and bond model studied by real-time TDDFT elec- tronic stopping simulations: The case of water vapor, Radiation Physics and Chemistry 193, 109961 (2022)

    2022

  31. [39]

    Shepard and Y

    C. Shepard and Y. Kanai, Ion-type dependence of DNA electronic excitation in water under proton, α-particle, and carbon ion irradiation: A first-principles simulation study, The Journal of Physical Chemistry B 127, 10700 (2023)

    2023

  32. [40]

    N. E. Koval, F. Da Pieve, B. Gu, D. Mu˜ noz Santiburcio, J. Kohanoff, and E. Artacho, Nonlinear electronic stop- ping of negatively charged particles in liquid water, Phys. Rev. Res. 5, 033063 (2023)

    2023

  33. [41]

    Shepard, D

    C. Shepard, D. C. Yost, and Y. Kanai, Electronic exci- tation response of DNA to high-energy proton radiation in water, Phys. Rev. Lett. 130, 118401 (2023)

    2023

  34. [42]

    A. G. Borisov, D. S´ anchez-Portal, R. D. Mui˜ no, and P. M. Echenique, Building up the screening below the femtosec- ond scale, Chem. Phys. Lett. 387, 95 (2004)

    2004

  35. [43]

    Quijada, A

    M. Quijada, A. G. Borisov, I. Nagy, R. D. Mui˜ no, and P. M. Echenique, Time-dependent density-functional cal- culation of the stopping power for protons and antipro- tons in metals, Phys. Rev. A 75, 042902 (2007)

    2007

  36. [44]

    N. E. Koval, D. S´ anchez-Portal, A. G. Borisov, and R. D. Mui˜ no, Dynamic screening and energy loss of antiprotons colliding with excited Al clusters, Nucl. Instrum. Meth- ods Phys. Res. B 317, 56 (2013)

    2013

  37. [45]

    Matias, R

    F. Matias, R. C. Fadanelli, P. L. Grande, N. E. Koval, R. D. Mui˜ no, A. G. Borisov, N. R. Arista, and G. Schiwi- etz, Ground- and excited-state scattering potentials for the stopping of protons in an electron gas, J. Phys. B: At. Mol. Opt. Phys. 50, 185201 (2017)

    2017

  38. [46]

    Matias, T

    F. Matias, T. F. Silva, N. E. Koval, J. J. N. Pereira, P. C. G. Antunes, P. T. D. Siqueira, M. H. Tabacniks, H. Yoriyaz, J. M. B. Shorto, and P. L. Grande, Efficient computational modeling of electronic stopping power of organic polymers for proton therapy optimization, Sci. Rep...

    2024

  39. [47]

    Supplemental material, see url for a detailed description 7 of the TDDFT-Penn methodology

  40. [48]

    Gunnarsson and B

    O. Gunnarsson and B. I. Lundqvist, Exchange and corre- lation in atoms, molecules, and solids by the spin-density- functional formalism, Phys. Rev. B 13, 4274 (1976)

    1976

  41. [49]

    C. Auth, A. Mertens, H. Winter, and A. Borisov, Thresh- old in the stopping of slow protons scattered from the surface of a wide-band-gap insulator, Phys. Rev. Lett. 81, 4831 (1998)

    1998

  42. [50]

    N. E. Koval, A. G. Borisov, L. F. S. Rosa, E. M. Stori, J. F. Dias, P. L. Grande, D. S´ anchez-Portal, and R. D. Mui˜ no, Vicinage effect in the energy loss of h2 dimers: Experiment and calculations based on time- dependent density-functional theory, Phys. Rev. A 95, 062707 (2017)

    2017

  43. [51]

    Hayashi, N

    H. Hayashi, N. Watanabe, Y. Udagawa, and C. C. Kao, The complete optical spectrum of liquid water measured by inelastic x-ray scattering, Proceedings of the National Academy of Sciences of the United States of America 97, 6264 (2000)

    2000

  44. [52]

    The curves result from fitting experimental data ( ℏω < 100 eV) of liquid water [57], amorphous ice [58], hexagonal ice [58], an d water vapor

    and hexagonal ices [53], and water vapor [54] in the opti cal limit (ℏk = 0) as a function of the transferred energy, ℏω. The curves result from fitting experimental data ( ℏω < 100 eV) of liquid water [57], amorphous ice [58], hexagonal ice [58], an d water vapor. Real-time TD...

    1953

  45. [53]

    Daniels, Bestimmung der optischen konstanten von eis aus energie - verlustmessungen von schnellen elektronen, Optics Communications 3, 240 (1971)

    J. Daniels, Bestimmung der optischen konstanten von eis aus energie - verlustmessungen von schnellen elektronen, Optics Communications 3, 240 (1971)

    1971

  46. [54]

    Kobayashi, Optical spectra and electronic structure of ice, The Journal of Physical Chemistry 87, 4317 (1983)

    K. Kobayashi, Optical spectra and electronic structure of ice, The Journal of Physical Chemistry 87, 4317 (1983)

    1983

  47. [55]

    W. Chan, G. Cooper, and C. Brion, The electronic spec- trum of water in the discrete and continuum regions. Absolute optical oscillator strengths for photoabsorption (6–200 eV), Chemical Physics 178, 387 (1993)

    1993

  48. [56]

    Vos and P

    M. Vos and P. L. Grande, Dielectric functions, their prop- erties and their relation to observables: Investigations using the Chapidif program for the case of aluminum, Computer Physics Communications 314, 109657 (2025)

    2025

  49. [57]

    D. Y. Smith, Dispersion theory, sum rules, and their ap- plication to the analysis of optical data, in Handbook of Optical Constants of Solids , edited by E. D. Palik (Aca- demic Press, San Diego, 1998) Chap. 3, pp. 35–68

    1998

  50. [58]

    Garcia-Molina, I

    R. Garcia-Molina, I. Abril, C. D. Denton, S. Heredia- Avalos, I. Kyriakou, and D. Emfietzoglou, Calculated depth-dose distributions for H + and He + beams in liquid water, Nuclear Instruments and Methods in Physics Re- search Section B: Beam Interactions with Materials and Atom...

    2009

  51. [59]

    Emfietzoglou, H

    D. Emfietzoglou, H. Nikjoo, I. Petsalakis, and A. Pathak, A consistent dielectric response model for water ice over the whole energy–momentum plane, Nuclear Instruments and Methods in Physics Research Section B: Beam Inter- actions with Materials and Atoms 256, 141 (2007)

    2007

  52. [60]

    Heredia-Avalos, R

    S. Heredia-Avalos, R. Garcia-Molina, J. M. Fern´ andez- Varea, and I. Abril, Calculated energy loss of swift He, Li, B, and N ions in SiO 2, Al 2O3, and ZrO 2, Physical Review A - Atomic, Molecular, and Optical Physics 72, 052902 (2005)

    2005

  53. [61]

    N. D. Mermin, Lindhard dielectric function in the relaxation-time approximation, Physical Review B - Con- densed Matter and Materials Physics 1, 2362 (1970)

    1970

  54. [62]

    R. F. Egerton, Electron Energy-Loss Spectroscopy in the Electron Microscope, 3rd ed. (Springer, New York, 2011)

    2011

  55. [63]

    J. F. Ziegler, M. Ziegler, and J. Biersack, SRIM – The stopping and range of ions in matter (2010), Nuclear In- struments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 268, 1818 (2010)

    2010

  56. [64]

    Kamitsubo, Heavy Ion Science, Oyo Buturi (Japan) 43, 1019 (1974)

    H. Kamitsubo, Heavy Ion Science, Oyo Buturi (Japan) 43, 1019 (1974)

    1974

  57. [65]

    Graphs, Data, Comments and Programs, https:// www-nds.iaea.org/stopping (2021)

    International Atomic Energy Agency / Nuclear Data Section, Electronic Stopping Power of Matter for Ions. Graphs, Data, Comments and Programs, https:// www-nds.iaea.org/stopping (2021)

    2021

  58. [66]

    Garcia-Molina, I

    R. Garcia-Molina, I. Abril, S. Heredia-Avalos, I. Kyri- akou, and D. Emfietzoglou, A combined molecular dy- namics and Monte Carlo simulation of the spatial distri- bution of energy deposition by proton beams in liquid water, Physics in Medicine and Biology 56, 6475 (2011). Sup...

    2011

  59. [67]

    A. G. Borisov, D. S´ anchez-Portal, R. D. Mui˜ no, and P. M. Echenique, Building up the screening below the femtosecond scale, Chem. Phys. Lett. 387, 95 (2004)

    2004

  60. [68]

    Quijada, A

    M. Quijada, A. G. Borisov, I. Nagy, R. D. Mui˜ no, and P. M. Echenique, T ime-dependent density-functional calculation of the stopping power for protons and ant iprotons in metals, Phys. Rev. A 75, 042902 (2007)

    2007

  61. [69]

    N. E. Koval, D. S´ anchez-Portal, A. G. Borisov, and R. D. Mui˜ no, Dynam ic screening and energy loss of antiprotons colliding with excited Al clusters, Nucl. I nstrum. Methods Phys. Res. B 317, 56 (2013)

    2013

  62. [70]

    Matias, R

    F. Matias, R. C. Fadanelli, P. L. Grande, N. E. Koval, R. D. Mui˜ no, A. G. Borisov, N. R. Arista, and G. Schiwietz, Ground- and excited-state scattering pote ntials for the stopping of protons in an electron gas, J. Phys. B: At. Mol. Opt. Phys. 50, 185201 (2017)

    2017

  63. [71]

    D. R. Penn, Electron mean-free-path calculations using a model d ielectric function, Phys. Rev. B 35(2), 482 (1987)

    1987

  64. [72]

    Vos and P

    M. Vos and P. L. Grande, Extension schemes of the dielectric funct ion, and their implications for ion stopping calculations, Journal of Physics and Chemistry of Solids 133, 187 (2019)

    2019

  65. [73]

    Matias, T

    F. Matias, T. F. Silva, N. E. Koval, J. J. N. Pereira, P. C. G. Antunes, P. T. D. Siqueira, M. H. Tabacniks, H. Yoriyaz, J. M. B. Shorto, and P. L. Grande, Efficient computati onal modeling of electronic stopping power of organic polymers for proton therapy optimi zation, Sci. R...

    2024

  66. [74]

    Gunnarsson and B

    O. Gunnarsson and B. I. Lundqvist, Exchange and correlation in atoms, mol ecules, and solids by the spin-density-functional formalism, Phys. Rev. B 13, 4274 (1976)

    1976

  67. [75]

    C. Auth, A. Mertens, H. Winter, and A. Borisov, Threshold in the stop ping of slow protons scattered from the surface of a wide-band-gap insulator, Phys. Rev. Let t. 81, 4831 (1998)

    1998

  68. [76]

    N. E. Koval, A. G. Borisov, L. F. S. Rosa, E. M. Stori, J. F. Dias, P. L. Gran de, D. S´ anchez- Portal, and R. D. Mui˜ no, Vicinage effect in the energy loss of h2 dimers: E xperiment and calculations based on time-dependent density-functional theory, P hys. Rev. A 95, 062707 ...

    2017

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