Non-Franck--Condon 2sigma/sup -1//sub u/ vibrational distributions in N/sup +//sub 2/. An interchannel-coupled shape resonance observed by dispersed fluorescence

Journal Article · Thu May 01 04:00:00 EDT 1986 · J. Chem. Phys.; (United States)

OSTI ID:6008293

Poliakoff, E D; Ho, M; Leroi, G E; White, M G

We report evidence for a molecular interchannel-coupled shape resonance in N/sub 2/ photoionization, observable in the vibrational branching ratios for the N/sup +//sub 2/(B /sup 2/..sigma../sup +//sub u/) state. The vibrational branching ratios for the N/sup +//sub 2/(B /sup 2/..sigma../sup +//sub u/) state are determined from vibrationally resolved dispersed fluorescence measurements on the N/sup +//sub 2/(B /sup 2/..sigma../sup +//sub u/..-->..X /sup 2/..sigma../sup +//sub g/) band system. The results demonstrate that the partial cross section for the N/sup +//sub 2/(B /sup 2/..sigma../sup +//sub u/,v' = 1) level is selectively enhanced in the photon energy range 28 ..epsilonsigma/sub u/ channel, and the observed enhancement is attributed to coupling between this channel and the 2sigma/sub u/..-->..epsilonsigma/sub g/ channel. Vibrational branching ratio curves for the excited state ion also show a pronounced peak at h..nu../sub exc/ = 22 eV, which shifts for the curves that sample the v' = 1 and v' = 2 levels of the ion, suggesting a few interpretations. The utility of coupling monochromatized fluorescence detection with synchrotron radiation excitation for extracting relative partial photoionization cross sections is demonstrated for the first time.

• Research Organization: Department of Chemistry, Boston University, Boston, Massachusetts 02215
• OSTI ID: 6008293
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 84:9; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
BRANCHING RATIO
BREMSSTRAHLUNG
ELECTROMAGNETIC RADIATION
ELECTRON SPECTROSCOPY
ELECTRONIC STRUCTURE
ELEMENTS
ENERGY LEVELS
EXCITED STATES
IONIZATION
NITROGEN
NONMETALS
PHOTOELECTRON SPECTROSCOPY
PHOTOIONIZATION
RADIATIONS
SPECTROSCOPY
SYNCHROTRON RADIATION
VIBRATIONAL STATES