Ab initio calculations of vibronic activity in phosphorescence microwave double resonance spectra of para-dichlorobenzene
2005 (English)In: Theoretical Chemistry accounts, ISSN 1432-881X, E-ISSN 1432-2234, Vol. 113, no 1, 15-27 p.Article in journal (Refereed) Published
The phosphorescence spectrum of p-dichlorobenzene has been calculated using multiconfiguration self-consistent-field wave functions and the quadratic response technique. Attention has been paid to the intensity distribution of the singlet-triplet (B-3(1u)->(1)A(g)) transition through a number of vibronic subbands. The second order spin-orbit coupling (SOC) contribution to the spin splitting of the B-3(1u) ((3)pi pi*) state is found to be almost negligible, and the calculations therefore provide a good estimate for the zero-field splitting (ZFS) parameters based only on the electron spin-spin coupling expectation values. Nuclear quadrupole resonance constants for the different Cl isotopes are also calculated to accomplish the ZFS assignment. The electric dipole activity of the spin sublevels in the triplet singlet transitions to the ground-state vibrational levels is estimated by calculations of derivatives using distorted geometries which are shifted from the equilibrium position along different vibrational modes. A vibrational analysis of the phosphorescence spectrum, based on the SOC-induced mixing of the singlet and triplet states calculated along different vibrational modes, provides reasonable agreement with experimental data.
Place, publisher, year, edition, pages
2005. Vol. 113, no 1, 15-27 p.
phosphorescence microwave double resonance spectra; vibronic activity; p-dichlorobenzene; quadratic response methodology; zero-field splitting parameters
IdentifiersURN: urn:nbn:se:kth:diva-5084DOI: 10.1007/s00214-004-0596-xISI: 000227633400002ScopusID: 2-s2.0-14644440780OAI: oai:DiVA.org:kth-5084DiVA: diva2:7839
QC 201008252005-04-282005-04-282010-08-25Bibliographically approved