The modified all‐valence INDO method with the inclusion of spin–orbit coupling

Abstract

The all-valence INDO method has been modified for the inclusion of spin-orbit coupling effects. In the method presented, the Hamiltonian includes spin-orbit coupling and the basis set constitutes the singlet and triplet determinental wave functions constructed from molecular orbitals resulting from nonrelativistic calculations. Eigenvectors obtained are later used for the evaluation of transition probabilities among different states. The results presented include lifetimes of different states of organic molecules and transition energies for halogen molecules and they are in a good agreement with experimental results.

Photoluminescence and quantum chemical studies of electronic and optical properties of m-nitroaniline and m-nitrophenol crystals

“…Potentials, charges and total energy became self-consistent after three to four iterative runs.21 Energies and oscillator strengths of singletÈtriplet transitions were calculated by the method described in ref. 22. Hyperpolarizabilities of radical ions were computed by the AM1 method.23…”

Fully relativistic calculations on the potential energy surfaces of the lowest 23 states of molecular chlorine

“…The results are compared with those of Peyerimhoff and Buenker, 26 Roszak and Lipinski, 27 and available experimental data. 9,13,14,47 The assignment is given to the states based on their main character at the ground state R e .…”

“…[20][21][22][23][24][25] The first ab initio potential curves for the Cl 2 molecule were computed by Peyerimhoff and Buenker 26 more than 25 years ago under the ⌳-⌺ approximation and served as the mainly theoretical basis for analysis of experimental data. Although semiempirical relativistic intermediate neglect of differential overlap ͑INDO͒ calculations were performed in Cl 2 15 years ago, 27 only recently, ab initio calculations including spin-orbit coupling have been performed [28][29][30][31][32][33] for some low lying valence states ͑usually͒ applying a relativistic core potential approach. Therefore, high accurate theoretical potential curves are of interest to understand Cl 2 spectra, as well as the analysis of nonadiabatic processes 34 and experimental data regarding the Cl 2 dissociation.…”