T/sub 1/ barrier height, S/sub 1/--T/sub 1/ intersystem crossing rate, and S/sub 0/ radical dissociation threshold for H/sub 2/CO, D/sub 2/CO, and HDCO

Journal Article · Thu Oct 01 00:00:00 EDT 1987 · J. Chem. Phys.; (United States)

OSTI ID:6286062

Chuang, M; Foltz, M F; Moore, C B

Vacuum UV laser-induced fluorescence has been used to detect the atomic products in the photofragmentation of H/sub 2/CO, D/sub 2/CO, and HDCO. The dissociation is shown to occur on both the ground (S/sub 0/) and the first triplet (T/sub 1/) potential surfaces. The T/sub 1/ exit barrier height (2.9--6.0 kcal/mol) and the S/sub 1/..-->..T/sub 1/ intersystem crossing rate near the T/sub 1/ barrier top (4 x 10/sup 7/ s/sup -1/) have been determined experimentally. The threshold energy for the radical dissociation channel on the S/sub 0/ surface, 86.57 +- 0.16 kcal/mol, has also been measured accurately by rovibronically resolved photolysis. The best values for the heat of formation (9.99 +- 0.19 kcal/mol) and the C--H bond enthalpy (15.69 +- 0.19 kcal/mol) of HCO radical have been derived from the measured threshold energies as well.

• Research Organization: Department of Chemistry, University of California Berkeley, California 94720; Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory Berkeley, California 94720
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6286062
• Journal Information: J. Chem. Phys.; (United States), Vol. 87:7
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
DEUTERIUM COMPOUNDS
PHOTOLYSIS
FORMALDEHYDE
FORMYL RADICALS
FORMATION HEAT
CHEMICAL BONDS
DISSOCIATION
POTENTIAL ENERGY
ACYL RADICALS
ALDEHYDES
CHEMICAL REACTIONS
DECOMPOSITION
ENERGY
ENTHALPY
HYDROGEN COMPOUNDS
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHYSICAL PROPERTIES
RADICALS
REACTION HEAT
THERMODYNAMIC PROPERTIES
400500* - Photochemistry