Multiphoton ionization study of the photodissociation dynamics of the S/sub 2/ state of CH/sub 3/ONO

Journal Article · Sun Jan 15 04:00:00 EST 1989 · J. Chem. Phys.; (United States)

OSTI ID:6596712

Winniczek, J W; Dubs, R L; Appling, J R; McKoy, V; White, M G

Two-color (1+1) REMPI (resonantly enhanced multiphoton ionization) photoelectron spectroscopy is used to probe the NO photofragments produced by the UV photodissociation of methyl nitrite, i.e., CH/sub 3/ONO+h..nu -->..CH/sub 3/ONO*(S/sub 2/)..-->..CH/sub 3/Ox(X)+NO(X, v, J). The photofragments are produced in their ground electronic states but with high rotational and translational energy. NO fragment angular distributions, rotational state distributions, and spatial alignment are determined by photoion and photoelectron detection. The initial state alignment is obtained by the CDAD (circularly dichroic angular distribution) technique for the first time. CDAD measurements for rotational levels with 35.5less than or equal toJless than or equal to46.5 result in alignment parameters at the classical high-J limit of A-script/sup (2)//sub 0/ = -0.4. This alignment is consistent with an ''impulsive'' dissociation mechanism in which photofragment recoil along the CH/sub 3/O--NO bond imparts substantial rotational angular momentum to the NO molecule resulting in a high-J state distribution and preferential rotation in the plane of dissociation. These measurements clearly establish the utility of the CDAD method for probing chemical processes in which spatial alignment plays an important role. Photoion angular distributions are used to probe correlations between the CH/sub 3/ONO transition dipole moment, NO fragment velocity, and angular momentum. These correlations reveal additional details of the photolysis mechanism.

• Research Organization: Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973
• OSTI ID: 6596712
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 90:2; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
ANGULAR DISTRIBUTION
CHALCOGENIDES
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
DECOMPOSITION
DISTRIBUTION
ELECTRON SPECTROSCOPY
IONIZATION
MULTI-PHOTON PROCESSES
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOELECTRON SPECTROSCOPY
PHOTOIONIZATION
PHOTOLYSIS
SPECTROSCOPY
YIELDS