An alternative formulation of the atomic axial tensor (AAT) of vibrational circular dichroism as the frequency derivative at zero frequency of a linear response function for operators referencing a nuclear displacement and a magnetic field is presented [1]. When used in the density matrix-based quasienergy derivative Lagrangian approach of Thorvaldsen et al.[2], this allows to express the AAT in a form where the need to solve response equations for the nuclear displacements is removed, significantly reducing the computation cost compared to existing formulations . The formalism also straightforwardly accounts for all contributions arising from the use of perturbation dependent basis sets.
It is also expected to pave the way for gauge-origin independent implementations of VCD within non-variational wave-function theories.
References
[1] S. Coriani , A. J. Thorvaldsen, K. Kristensen and Poul Jørgensen,
Phys. Chem. Chem. Phys.13 4224-4229 (2011)
[2] A. Thorvaldsen, K. Ruud, K. Kristensen, P. Jørgensen and
S. Coriani, J. Chem. Phys. 129 214108 (2008).
