A quantum dynamical examination of the vibronic structure of singlet and triplet spectra of acetyleneDedicated to Professor F. Dörr on the occasion of his 80th birthday

Autor:	Horst Köppel, Georg Hohlneicher, Karsten Malsch, Rainer Schork
Rok vydání:	2001
Předmět:	Vibronic coupling Atomic orbital Chemistry Excited state General Physics and Astronomy Vibronic spectroscopy Electronic structure Singlet state Physical and Theoretical Chemistry Atomic physics Basis set Molecular electronic transition
Zdroj:	Physical Chemistry Chemical Physics. 3:5393-5407
ISSN:	1463-9084 1463-9076
Popis:	The intensity distributions for the optical transitions S0 → S1 and S1 → S0 and the electron impact induced transitions S0 → Tn (n = 1–3) were calculated using quantum dynamical methods. The problem was analyzed in three degrees of freedom, the CC-bond length and the two CCH-bond angles. The three-dimensional potential energy surfaces needed for such a treatment were calculated at the CASPT2 level employing an ANO-type basis set and an active space that consisted of 10 electrons in 10 orbitals. The complex intensity distribution of the S0 ↔ S1 transition in absorption and emission is reproduced in great detail. Spectral quantization allows an analysis of the modes that dominate vibronic coupling. Most of these modes bear no resemblance to the normal modes of the trans and cis form of S1 . An emission from a higher excited state starting at 6.23 eV could tentatively be assigned to T4 . T2 and T3 most likely do not contribute to the first band observed in the electron energy loss (EEL) spectrum. The same is true for the band that starts at 6.6 eV in the EEL spectrum. It results mostly from S1 and possibly in part from T4 .
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::f26fa3ce14b7a752fb68eaedd6302932 https://doi.org/10.1039/b106391j Zobrazit plný text záznamu