Effective Inclusion of Mechanical and Electrical Anharmonicity in Excited Electronic States: VPT2-TDDFT Route
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posted on 2017-04-28, 00:00 authored by Franco Egidi, David B. Williams-Young, Alberto Baiardi, Julien Bloino, Giovanni Scalmani, Michael J. Frisch, Xiaosong Li, Vincenzo BaroneWe present a reliable and cost-effective
procedure for the inclusion
of anharmonic effects in excited-state energies and spectroscopic
intensities by means of second-order vibrational perturbation theory.
This development is made possible thanks to a recent efficient implementation
of excited-state analytic Hessians and properties within the time-dependent
density functional theory framework. As illustrated in this work,
by taking advantage of such algorithmic developments, it is possible
to perform calculations of excited-state infrared spectra of medium-large
isolated molecular systems, with anharmonicity effects included in
both the energy and property surfaces. We also explore the use of
this procedure for the inclusion of anharmonic effects in the simulation
of vibronic bandshapes of electronic spectra and compare the results
with previous, more approximate models.
