Experimental and theoretical investigations of the threshold photoelectron spectrum of the CH2 radical

Coudert, L. H.

Permalink

https://hdl.handle.net/2142/100563 Copy

Description

Title

Experimental and theoretical investigations of the threshold photoelectron spectrum of the CH2 radical

Author(s)

Coudert, L. H.

Contributor(s)

• Alcaraz, C.
• Garcia, G. A.
• Loison, J.-C.
• Holzmeier, F.
• Gans, B.

Issue Date

2018-06-20

Keyword(s)

Mini-symposium: New Ways of Understanding Molecular Spectra

Abstract

The methylene cation CH+ 2 is spectroscopically poorly characterized as it is difficult to produce in large amounts. It is subject to the Renner-Teller effect giving rise to ground Xe+ 2A1 and excited Ae+ 2B1 electronic states. Photoelectron spectroscopy of the methylene radical CH2 allows us to gain information about both CH2 and its cation. The former is also theoretically challenging as it is a very non-rigid species characterized by a barrier to linearity of less than 2000 cm−1 in its ground Xe 3B1 electronic state. The first photoelectron spectra of CH2 were investigated using pulsed-field-ionization zerokinetic-energy spectroscopy.a A rotationally resolved spectrum containing Xe+ 2A1 ← Xe 3B1 transitions was recorded from 83600 to 84070 cm−1 and analyzed in terms of CH+ 2 rotational constants. The threshold photoelectron spectrum of CH2 has been recorded from 9.8 to 12 eV (79040 to 96800 cm−1 ) using a recently developed flow tube reactorb and VUV synchrotron radiation. This new spectrum spans a larger energy range than the previous ones,a but with less resolution. It displays narrow and broad features due respectively to the Xe+ 2A1 ← Xe 3B1 and Ae+ 2B1 ← Xe 3B1 ionizing transitions. Using new ab initio potential energy surfaces and available ones,c the photoelectron spectrum is currently being computed using two models. The first one accounts for the large amplitude bending mode and the rotation only; the second one, also accounts for the stretching modes. The experimental and theoretical spectra will be discussed in the paper.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/100563

DOI

10.15278/isms.2018.WB07

Copyright and License Information

Copyright 2018 L.H. Coudert

Owning Collections