Strong laser alignment of solvent-solute aggregates in the gas-phase

Strong quasi-adiabatic laser alignment of the indole-water-dimer clusters, an amino-acid chromophore bound to a single water molecule through a hydrogen bond, was experimentally realized. The alignment was visualized through ion and electron imaging following strong-field ionization. Molecular-frame photoelectron angular distributions showed a clear suppression of electron yield in the plane of the ionizing laser's polarization, which was analyzed as strong alignment of the molecular cluster with $\left< \cos^2\theta_{2D} \right> \ge$ 0.9.