We extend our previous definition of the metric Δr for electronic excitations in the framework of the time-dependent density functional theory [C. A. Guido, P. Cortona, B. Mennucci, and C. Adamo, J. Chem. Theory Comput.9, 3118 (2013)], by including a measure of the difference of electronic position variances in passing from occupied to virtual orbitals. This new definition, called Γ, permits applications in those situations where the Δr-index is not helpful: transitions in centrosymmetric systems and Rydberg excitations. The Γ-metric is then extended by using the Natural Transition Orbitals, thus providing an intuitive picture of how locally the electron density changes during the electronic transitions. Furthermore, the Γ values give insight about the functional performances in reproducing different type of transitions, and allow one to define a “confidence radius” for GGA and hybrid functionals.
Autori interni: | |
Autori: | Ciro Achille Guido; Pietro Cortona; Carlo Adamo |
Titolo: | Effective electron displacements: A tool for time-dependent density functional theory computational spectroscopy |
Anno del prodotto: | 2014 |
Digital Object Identifier (DOI): | 10.1063/1.4867007 |
Appare nelle tipologie: | 1.1 Articolo in rivista |