TY - JOUR
T1 - Spectral broadening and diffusion by torsional motion in biphenyl
AU - Beenken, Wichard J.D.
AU - Lischka, Hans
N1 - Funding Information:
The authors like to thank M. Barbatti, A. Karpfen, S. Westenhoff, and A. Yartsev for fruitful discussions and the Austrian Science Fund for financial support (Project P14817-N03). The calculations were performed in part on the Schrödinger II cluster of the University of Vienna.
PY - 2005/10/8
Y1 - 2005/10/8
N2 - We have studied biphenyl by time-dependent density-functional theory. In particular, we have analyzed the dependence of singlet excitation energies and transition dipoles on the torsional angle between the phenyl groups. The torsional spectrum has been computed quantum mechanically as well as semiclassically in order to understand how this influences the broadening of absorption and luminescence spectra. Our results are in best agreement with supersonic jet spectroscopy data, but also fit astonishingly well to spectra of biphenyl in condensed phase. Furthermore, we compare the torsional and vibrational relaxation and discuss qualitatively the general consequences for poly-para-phenylenes and related conjugated polymers as poly-thiophenes, considering, in particular, how side chains and solvents may affect the optical spectra.
AB - We have studied biphenyl by time-dependent density-functional theory. In particular, we have analyzed the dependence of singlet excitation energies and transition dipoles on the torsional angle between the phenyl groups. The torsional spectrum has been computed quantum mechanically as well as semiclassically in order to understand how this influences the broadening of absorption and luminescence spectra. Our results are in best agreement with supersonic jet spectroscopy data, but also fit astonishingly well to spectra of biphenyl in condensed phase. Furthermore, we compare the torsional and vibrational relaxation and discuss qualitatively the general consequences for poly-para-phenylenes and related conjugated polymers as poly-thiophenes, considering, in particular, how side chains and solvents may affect the optical spectra.
UR - http://www.scopus.com/inward/record.url?scp=26944447464&partnerID=8YFLogxK
U2 - 10.1063/1.2049269
DO - 10.1063/1.2049269
M3 - Article
AN - SCOPUS:26944447464
SN - 0021-9606
VL - 123
JO - The Journal of Chemical Physics
JF - The Journal of Chemical Physics
IS - 14
M1 - 144311
ER -