A CNDO/S study of the importance of electron repulsion parameters and charge density changes on the weakness of the v8(e2g) vibronic activity in the benzene 260 nm band
✍ Scribed by David Theiste; Richard D. Jones; Patrik R. Callis
- Publisher
- Elsevier Science
- Year
- 1987
- Tongue
- English
- Weight
- 613 KB
- Volume
- 133
- Category
- Article
- ISSN
- 0009-2614
No coin nor oath required. For personal study only.
✦ Synopsis
We investigate the disparity between the large observed ratio ( x 100: 1) of vg to vg vibrationally induced intensity in the 260 nm ( 'BZU-'AI,) absorption band of benzene and that computed from CNDOlS and INDO/S (typically 4: 1). The calculated vs intensity is relatively insensitive to small admixtures of the vg mode, but is found to be quite sensitive to the nature of the semiempirical electron repulsion integral (y) distance dependence. A new perturbation theory is applied successfully which relates the vibronic coupling directly to changes in the Fock matrix and the simple first-order transition density.