Electron-vibration coupling in time-dependent density-functional theory: Application to benzene

As a test of the time-dependent density-functional theory (TDDFT) for elect ron-vibration coupling, we apply it to the optical properties of the pi-pi* transitions in benzene. Quantities calculated are the envelopes of the Fra nck-Condon factors of the electronic transitions and the oscillator strengt hs of symmetry-forbidden transitions. The strengths of the pi-pi* transitio ns span three orders of magnitude and are reproduced to better than 35% by the theory. Comparable agreement is found for the Franck-Condon widths. We conclude that rather detailed information about the effects of the electron -vibrational coupling can be obtained with the TDDFT. (C) 2001 American Ins titute Of Physics.