Investigation of excited state structural dynamics of bis(2-thienyl)ketone in the condensed phase using Raman, IR, and UV-visible spectroscopy aided by density functional theory calculation

J Phys Chem B. 2010 Dec 23;114(50):16847-53. doi: 10.1021/jp109182h. Epub 2010 Nov 30.

Abstract

Detailed investigation on the vibrational and electronic spectra has been carried out in order to study various properties of bis(2-thienyl)ketone molecule in its ground and excited electronic states. To get insight into the structural and symmetry features of the molecule, resonance Raman spectra (RRs) of bis(2-thienyl)ketone have been acquired and the Raman excitation profiles of several normal modes have been analyzed, and density functional calculations were done to help the elucidation of the photo relaxation dynamics of A and B band electronic transitions. The RRs indicate that the photo relaxation dynamics for S(0)→S(2) excited electronic state is predominantly along the nominal the Ring breathing + ν(SynC(1)C(11) C(9)) stretch, ν(CO) + ν(C(2)C(3)) + ν(C(8)C(9)) stretch, and the γ(CH(I, II)) + γ(OC) stretch and simultaneously along the nominal γ(CH(II)) relaxation processes, while that for S(0)→S(5) is predominantly along the ν(CO) + ν(C(2)C(3)) + ν(C(8)C(9)) stretch ν(7) (1616 cm(-1)). The excited state short-time structural dynamics of bis (2-thienyl) ketone determined from RRs were interpreted with account of the Albrecht's theory and Herzberg-Teller contributions.