## Files in this item

FilesDescriptionFormat

application/vnd.openxmlformats-officedocument.presentationml.presentation

1368543.pptx (3MB)
PresentationMicrosoft PowerPoint 2007

application/pdf

3729.pdf (23kB)
AbstractPDF

## Description

 Title: CH3 INTERNAL ROTATION IN 9-METHYLANTHRACENE Author(s): Baba, Masaaki Contributor(s): Hougen, Jon T.; Misono, Masatoshi Subject(s): Large amplitude motions, internal rotation Abstract: We observed the rotationally resolved fluorescence excitation spectrum of the S$_1$ $\leftarrow$ S$_0$ transition of jet-cooled 9-methylanthracene. The potential energy curve for CH$_3$ internal rotation is six-fold symmetric. The barrier to rotation ($V_6$) is $\sim$ 120 cm$^{-1}$ [2], which is considerably larger than that of toluene ( $\sim$ 5 cm$^{-1}$ ) [1]. The $V_6$ value is the energy difference between two isomers {\textquoteleft}$staggered${\textquoteright} and {\textquoteleft}$eclipsed${\textquoteright}. The main contribution to $V_6$ is expected to be hyperconjugation, which is the $\pi$-like interaction between the aromatic $\pi$ orbital and methyl sp$^3$ orbital. The final goal of this work is to quantitatively elucidate the vibrational and rotational energy levels for CH$_3$ internal rotation. It is essential to observe the high-resolution and high-precision electronic spectra and theoretically search the best effective Hamiltonian to reproduce the experimental results. We are now developing a new laser control system with optical frequency comb locked to GPS, and an ab initio method which provides the reliable potential energy curve. \\[-1mm] \begin{flushleft} [1] M. Baba, et al., J. Phys. Chem. A {\bf 113}, 2369 (2009) \\[1mm] [2] D. R. Borst and D. W. Pratt, J. Chem. Phys. {\bf 113}, 3658 (2000) \end{flushleft} Issue Date: 2019-06-17 Publisher: International Symposium on Molecular Spectroscopy Genre: Conference Paper / Presentation Type: Text Language: English URI: http://hdl.handle.net/2142/104573 DOI: 10.15278/isms.2019.MI08 Rights Information: Copyright 2019 Masaaki Baba Date Available in IDEALS: 2019-07-152020-01-25
﻿