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A reinterpretation of the electronic spectrum of pyrrole: a quantum dynamics study.

A reinterpretation of the electronic spectrum of pyrrole: a quantum dynamics study.

Authors :
Neville SP
Worth GA
Source :
The Journal of chemical physics [J Chem Phys] 2014 Jan 21; Vol. 140 (3), pp. 034317.
Publication Year :
2014

Abstract

The first band in the electronic spectrum of pyrrole is calculated from wavepacket propagations performed using the MCTDH method. To do so, two model Hamiltonians are constructed to describe seven low-lying excited electronic states of pyrrole. These Hamiltonians are based on the vibronic coupling model, and are parameterised via fitting to extensive CASPT2 and EOM-CCSD calculations. A detailed analysis of the structure of pyrrole's electronic spectrum in the range 5.5 to 6.5 eV is made. The role of intensity borrowing from transitions to ππ(*) states by lower-lying 3s and 3p Rydberg states is assessed, and reassignments of much of the spectrum are subsequently made which indicate that most of the states in the spectrum are predominantly Rydberg in character. The resulting conclusions drawn serve to highlight the limitations of assignments based on the matching of calculated vertical excitation energies and the positions of peak maxima observed in electronic spectra.

Details

Language :
English
ISSN :
1089-7690
Volume :
140
Issue :
3
Database :
MEDLINE
Journal :
The Journal of chemical physics
Publication Type :
Academic Journal
Accession number :
25669389
Full Text :
https://doi.org/10.1063/1.4861223