Full Empirical Potential Curves And Improved Dissociation Energies For The X 1σ+ And A 1π States Of Ch+

Cho, Young-Sang

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https://hdl.handle.net/2142/50779 Copy

Description

Title

Full Empirical Potential Curves And Improved Dissociation Energies For The X 1σ+ And A 1π States Of Ch+

Author(s)

Cho, Young-Sang

Contributor(s)

Le Roy, Robert J.

Issue Date

2014-06-16

Keyword(s)

Small molecules

Abstract

"CH$^+$ has been a species of interest since the dawn of molecular astrophysics,\footnote{\,A.E.\ Douglas and G.\ Herzberg, Astrophys.\,J.\ {\bf 94}, 381 (1941).} and it is an important intermediate in combustion processes. In the domain of `conventional' spectroscopy there have been a number of studies of low $v'$ and $v''$ portions of the $A\,^1\Pi-X\,^1\Sigma^+$ band system of various isotopologues, and Amano recently reported microwave measurements of the ground-state $R(0)$ lines of $^{12}$CH$^+$, $^{13}$CH$^+$ and $^{12}$CD$^+$.\footnote{\,T.\ Amano, Astrophys.\ J.\ Lett.\ {716}, L1 (2010)}~ In addition, Helm {\it et al.}\footnote{\,H.\ Helm, P.C.\ Crosby, M.M.\ Graff and J.T.\ Mosley, Phys.\ Rev.\ {\bf A 25}, 304 (1982)}\ used photodissociation spectroscopy to observe transitions to very high-$J'$ tunneling-predissociation levels (shape resonances) involving $v(A)=0-10$, for many of which they also measured the photo-fragment kinetic energy release. More recently Hechtfischer {\it et al.}\ used photodissociation spectroscopy of `Feschbach resonance' levels at very high $v'(A)$ and low $J'$ to obtain the first direct measurement of the $^{12}$CH$^+$ dissociation energy with near-spectroscopic accuracy ($\pm 1.1$ cm$^{-1}$).\footnote{\,U.\ Hechtfischer and C. J.\ Williams, M.\ Lange, J.\ Linkemann, D.\ Schwalm, R.\ Wester, A.\ Wolf and D.\ Zajfman, J.Chem.Phys.\ {\bf 117}, 8754 (2002).} However, to date, all analyses of the data for this system had been performed using traditional band-constant or Dunham-expansion fits to data for the lowest vibrational levels,\footnote{H.S.P.\ M{\""u}ller, Astron.\ Astrophys.\ {\bf 514}, L7 (2010)} and there have been no attempts to combine the `conventional' low-$v$ data with the high-$J'$ and high-$v'$ photodissociation data in a single treatment. The present work has addressed this problem by performing a Direct-Potential-Fit (DPF) analysis that obtains full analytic potential energy functions for the $X\,^1\Sigma^+$ and $A\,^1\Pi$ states of CH$^+$ that are able to account for all of the available data (on average) within their uncertainties."

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/50779

DOI

https://doi.org/10.15278/isms.2014.MG02

Copyright and License Information

Copyright 2014 by the authors. Licensed under a Creative Commons Attribution 4.0 International License. http://creativecommons.org/licenses/by/4.0/

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