540--900 nm photodissociation of 300 K NCNO: One- and two-photon processes

Journal Article · Sun Jul 15 04:00:00 EDT 1984 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.447746· OSTI ID:6741867

Nadler, I; Pfab, J; Reisler, H; Wittig, C

The laser photodissociation of 300 K NCNO throughout the region 540--900 nm is reported, and both 1- and 2-photon processes are discussed. By monitoring CN fragments produced via the 1-photon process, we show that with photolysis wavelengths >592 nm, dissociation occurs predominantly by exciting NCNO ''hot bands.'' At shorter photolysis wavelengths, dissociation from the ground vibrational state of NCNO is observed as well, but the contributions from hot bands are still manifest in high CN rotational levels which are energetically inaccessible from the ground state (D/sub 0/ = 48.8 kcal mol/sup -1/). Energy distributions in the CN fragments were determined for excess energies up to 1800 cm/sup -1/, and are in agreement with phase space theory calculations and a vibrational predissociation mechanism. In addition, throughout the region 620--900 nm, stepwise two-photon photodissociation proceeds using the A /sup 1/A'' state as a gateway, and results in rotationally and vibrationally ''hot'' CN fragments. The hot CN fragment yield vs photolysis wavelength shows peaks which correspond exactly to peaks in the NCNO absorption spectrum, allowing us to obtain high resolution spectra of the A /sup 1/A''reverse arrow X /sup 1/A' absorption system. The one- and two-photon processes are in competition, and the latter disappears at wavelengths where one-photon photodissociation of NCNO via its ground vibrational level sets in. The nature of the electronic states involved in the one- and two-photon processes is also discussed.

• Research Organization: Department of Chemistry, University of Southern California, Los Angeles, California 90089-0484
• OSTI ID: 6741867
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 81:2; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640300* -- Atomic
Molecular & Chemical Physics
74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION SPECTRA
CHEMICAL REACTIONS
DECOMPOSITION
DISSOCIATION
MEDIUM TEMPERATURE
MULTI-PHOTON PROCESSES
NITROSO COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
SPECTRA