High-resolution Laser Spectroscopy Of S1←s0 Transition Of Trans-stilbene : Nonplanar Structure In The Ground State

Shimizu, Akira

Permalink

https://hdl.handle.net/2142/116699 Copy

Description

Title

High-resolution Laser Spectroscopy Of S1←s0 Transition Of Trans-stilbene : Nonplanar Structure In The Ground State

Author(s)

Shimizu, Akira

Contributor(s)

• Baba, Masaaki
• Misono, Masatoshi
• Kasahara, Shunji
• Nakajima, Kosuke

Issue Date

2022-06-23

Keyword(s)

Structure determination

Abstract

% back ground We have great interest in the excited-state dynamics of $\it{trans}$-stilbene such as $\it{cis}$-$\it{trans}$ isomerization in the electronic excited state. Zewail et al. reported the results of time-resolved spectroscopy and suggested its nonplanar structure in the ground S$_0$ state \footnote{J. A. Syage, P. M. Felker, and A. H. Zewail, J. Chem. Phys. {\bf 81}, 4685 (1984).}. In contrast, Pratt et al. concluded that the molecule is essentially planar both in the S$_0$ and S$_1$ states by analyzing the rotationally resolved high-resolution speoctrum of the S$_1$$\leftarrow$S$_0$ $0_0^0$ band \footnote{D. W. Pratt, W. L. Meerts et al., J. Phys. Chem. {\bf 94}, 6 (1990).}. % rotational constant We observed the spectrum with much higher accuracy and quality, and re-determined the rotational constants by high-resolution spectrum of $0_0^0$ bannd. Although it is impossible to accurate determine the abosolute value of rotational constant $A$ for the $a$-type transition, We could conclude that $\it{trans}$-stilbene is non-planar in the S$_0$ state. % my program In addition to estimate the molecular structure from observed rotational constants, we developed program. By this program, we estimated that phenyl rings are rotated approximately $\pm$10 degrees in S$_0$ state. % ab initio Theoretical calculation using WB97XD functional provided the phenyl rings are rotated 14 degrees in S$_0$ state and 2.4 degrees in S$_1$ state. WB97XD functional evaluate steric repulsion between H atoms of {\it ortho}-position in a phenyl ring and in an ethylene part by dispersion force potential semi-eprically. This result support non-planar structure revealed from the observed rotational constants.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Handle URL

https://hdl.handle.net/2142/116699&&

DOI

https://doi.org/10.15278/isms.2022.RL05

Copyright and License Information

Copyright 2022 held by the authors

Owning Collections