# Classical Magnetic Dipole Moments for the Simulation of Vibrational Circular Dichroism by ab Initio Molecular Dynamics

journal contribution

posted on 21.01.2016, 14:23 by Martin Thomas, Barbara KirchnerWe present a new approach for calculating
vibrational circular
dichroism spectra by ab initio molecular dynamics. In the context
of molecular dynamics, these spectra are given by the Fourier transform
of the cross-correlation function of magnetic dipole moment and electric
dipole moment. We obtain the magnetic dipole moment from the electric
current density according to the classical definition. The electric
current density is computed by solving a partial differential equation
derived from the continuity equation and the condition that eddy currents
should be absent. In combination with a radical Voronoi tessellation,
this yields an individual magnetic dipole moment for each molecule
in a bulk phase simulation. Using the chiral alcohol 2-butanol as
an example, we show that experimental spectra are reproduced very
well. Our approach requires knowing only the electron density in each
simulation step, and it is not restricted to any particular electronic
structure method.