Formation of electronically excited CO$sub 2$$sup +$ in collisions of H$sup +$, H, He$sup +$, and Ne$sup +$ with CO$sub 2$

Journal Article · Tue Jan 01 00:00:00 EST 1974 · J. Chem. Phys., v. 60, no. 1, pp. 264-269

OSTI ID:4354708

Haugh, M J; Birely, J H

Electronic excitation in collisions of 200 eV-25 keV H+, H, He+, and Ne+ with CO/sub 2/ has been investigated under single-collision conditions in an atomic beam experiment. For each of these projectiles, the B/sup 2/ SIGMA /sup +/ /sub u/ and A/sup 2/II/sub u/ states of CO/sub 2/+ are the dominant electronically excit ed species emitting in the 20O-500 nm wavelength range owing to target excitation. Although dissociative electron capture by He+ and Ne+ to form electronically excited CO+ minimizes the energy defect, no emission is observed from CO+ A/sup 2/II, and formation of CO+B/sup 2/ SIGMA /sup +/ is of only minor importance. The latter observations are in direct contradiction to predictions derived from the adiabatic criterion and demonstrate that, in the competition among allowed excitation processes, details of the electronic structure of the collision partners override energy considerations. The qualitative features of the emission spectrum excited by H/sup +/, H, and He/sup +/ are insensitive to relative velocity over the ener gy range covered. The ratio of the cross sections for excitation of CO/sub 2/+ B-X and A-X emissions is about 0.20 for H+ and 0.40 for He+. In Ne + impact, the CO/sub 2/+ A state vibrational distribution changes significantly, the (B-X)/(A-X) cross section ratio decreases from 0.46 to 0.07, and the relative importance of Ne and Ne+ emissions diminishes markedly as the energy is reduced from 4 keV to 200 eV. Our results are compared with those for electronic excitation produced by photoionization, electron impact, and Penning ionization of CO/sub 2/., (auth)

• Research Organization: Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122
• NSA Number: NSA-29-025184
• OSTI ID: 4354708
• Journal Information: J. Chem. Phys., v. 60, no. 1, pp. 264-269, Other Information: Orig. Receipt Date: 30-JUN-74
• Country of Publication: United States
• Language: English

Related Subjects

N60400* -Physics (Atomic & Molecular)-Collision Phenomena
*CARBON DIOXIDE- ION-MOLECULE COLLISIONS
*HELIUM IONS- ION- MOLECULE COLLISIONS
*HYDROGEN IONS 1 PLUS- ION-MOLECULE COLLISIONS
*HYDROGEN- ATOM-MOLECULE COLLISIONS
*NEON IONS- ION-MOLECULE COLLISIONS
ATOMIC BEAMS
CROSS SECTIONS
EMISSION SPECTRA
EV RANGE 100-1000
EXCITATION
ION BEAMS
IONIZATION
KEV RANGE 01-10
KEV RANGE 10-100