Dispersed fluorescence observations of the CO(A 1Π→X 1Σ+) transitions from photodissociation of CO2
Abstract
Spectra from 1500 to 1800 Å have been obtained showing CO(A 1Π→X 1Σ+) fluorescence arising from photodissociation of CO2. A line emission source provided the incident photons at 15 selected wavelengths from 449 to 955 Å. Analysis of the spectra confirms that the CO(A 1Π→X 1Σ+) band system dominates the vuv fluorescence at incident photon wavelengths from 700 to 923 Å. Vibrational populations of the CO(A 1Π) electronic state for v=0, 1, and 2 are seen to follow Poisson distributions. The onset of dissociation to CO(A 1Π)+O(1D) at 801 Å, the threshold for that process, is apparent from the relative increase in the A 1Π (v=0) population. At the minimum energy required to produce CO(A 1Π)+O(1S), no increase in the v=0 population is observed. Absolute partial cross sections for production of the CO(A→X) bands at incident photon wavelengths of 901.2 and 923.2 Å are reported. The data also show the electronic transition moment to decrease linearly with the r centroid to ∼1.25 Å, consistent with previously established results; however, at larger values of the r centroid the moment increases. The fluorescence observed using incident photons at still shorter wavelengths, 449 Å<λ<500 Å, consists primarily of atomic carbon lines, with an upper limit for the cross section for production of CO(A 1Π) of ∼0.07 Mb.
- Publication:
-
Journal of Chemical Physics
- Pub Date:
- April 1977
- DOI:
- 10.1063/1.434405
- Bibcode:
- 1977JChPh..66.3688P
- Keywords:
-
- Carbon Dioxide;
- Carbon Monoxide;
- Far Ultraviolet Radiation;
- Fluorescence;
- Gas Dissociation;
- Photodissociation;
- Cross Sections;
- Electron States;
- Electron Transitions;
- Molecular Energy Levels;
- Ultraviolet Spectra;
- Atomic and Molecular Physics;
- 82.50.Et;
- 33.50.Dq;
- Fluorescence and phosphorescence spectra