Towards a gauge invariant method for molecular chiroptical properties in TDDFT
Physical Chemistry Chemical Physics 11, 4481 - 4489 (2009)
Towards a gauge invariant method for molecular chiroptical properties in TDDFT
We present an efficient scheme to calculate the chiroptical response of molecular systems within time dependent functional theory using either a real-time propagation or a frequency-dependent Sternheimer methods. The scheme avoids the sum over empty orbitals commonly used and has a very favourable scaling with systems size. Moreover, the method is general and can be easily implemented. In the present work we implemented it using a real-space pseudo-potential representation of the wave-functions and Hamiltonian. The specific use of non-local pseudo-potentials to represent the ions implies that a gauge correction term in the angular momentum operator must be included, such that the total scheme is fully gauge invariant. Applications to small organic chiral molecules are shown and discussed, addressing some deficiencies of present exchange-correlation functionals to describe the absolute position of the excitations, but not the shape or sign of the dichroism spectra that comes in excellent agreement with available experiments.
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- http://dx.doi.org/10.1039/B903200B