Identifying complex Fermi resonances in p-difluorobenzene using zero-electron-kinetic-energy (ZEKE) spectroscopy

被引：11

作者：

Kemp, David J. ^{[1
]}

Gardner, Adrian M. ^{[1
,2
]}

Tuttle, William D. ^{[1
]}

Midgley, Jonathan ^{[1
]}

Reid, Katharine L. ^{[1
]}

Wright, Timothy G. ^{[1
]}

机构：

[1] Univ Nottingham, Sch Chem, Univ Pk, Nottingham NG7 2RD, England

[2] Univ Liverpool, Stephenson Inst Renewable Energy, Liverpool L69 7ZF, Merseyside, England

来源：

JOURNAL OF CHEMICAL PHYSICS | 2018年 / 149卷 / 09期

基金：

英国工程与自然科学研究理事会;

关键词：

THRESHOLD IONIZATION SPECTROSCOPY; METHYL INTERNAL-ROTATION; ION-DIP SPECTROSCOPY; PHOTOELECTRON-SPECTROSCOPY; VIBRATIONAL PREDISSOCIATION; MOLECULAR PHOTOIONIZATION; ANGULAR-DISTRIBUTIONS; FLUORESCENCE-SPECTRA; REMPI SPECTROSCOPY; RYDBERG STATES;

D O I：

10.1063/1.5045544

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The vibrations of the ground state cation ((X) over tilde B-2(2g)) of para-difluorobenzene (pDFB) have been investigated using zero-electron-kinetic-energy (ZEKE) spectroscopy. A comprehensive set of ZEKE spectra were recorded via different vibrational levels of the Si state (<0 degrees + 1300 cm(-1)). The adiabatic ionization energy for pDFB was measured as 73 869 +/- 5 cm(-1). Use of different intermediate levels allows different cationic vibrational activity to be obtained via the modification of the Franck-Condon factors for the ionization step, allowing the wavenumbers of different vibrational levels in the cation to be established. In addition, assignment of the vibrational structure in the ZEKE spectra allowed interrogation of the assignments of the S-1 <- S-0 transition put forward by Knight and Kable [J. Chem. Phys. 89, 7139 (1988)]. Assignment of the vibrational structure has been aided by quantum chemical calculations. In this way, it was possible to assign seventeen of the thirty vibrational modes of the ground state pDFB cation. Evidence for complex Fermi resonances in the S-1 state, i.e., those that involve more than two vibrations, was established. One of these was investigated using picosecond time-resolved photoelectron spectroscopy. In addition, we discuss the appearance of several symmetry-forbidden bands in the ZEKE spectra, attributing their appearance to a Rydberg state variation of an intrachannel vibronic coupling mechanism. Published by AIP Publishing.

引用

页数：20