A systematic four-dimensional approach to strong field control of molecular torsions

We introduce a four-dimensional quantum model for describing the torsional control of $\rm G_{16}$-type molecules in the electronic ground state, based on the symmetry-adapted variational method. We define conditions for which lower-dimensional models, commonly used to simulate the strong-field control of molecular torsions, are reliable approximations to a four-dimensional treatment. In particular, we study the role of different types of rotational-torsional couplings---the field-free coupling and the field-induced coupling---and show that the conclusions recently drawn on the role of rotational-torsional couplings in the process of torsional alignment are not correct. Furthermore, we demonstrate how important an adequate description of the molecular polarizability is for reliably predicting the torsional alignment.