Photodissociation dynamics of tert-butyl nitrite on Ag(111): Characterization of translationally and internally excited NO fragments

Citation
W. Zhao et al., Photodissociation dynamics of tert-butyl nitrite on Ag(111): Characterization of translationally and internally excited NO fragments, J PHYS CH A, 105(11), 2001, pp. 2234-2239
Citations number
46
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF PHYSICAL CHEMISTRY A
ISSN journal
1089-5639 → ACNP
Volume
105
Issue
11
Year of publication
2001
Pages
2234 - 2239
Database
ISI
SICI code
1089-5639(20010322)105:11<2234:PDOTNO>2.0.ZU;2-R
Abstract
The translational, vibrational, and rotational characteristics of nitric ox ide, NO, ejected by 351 nm photodissociation of tert-butyl nitrite, (CH3)(3 )CONO, adsorbed on Ag(lll) have been investigated using resonance-enhanced multiphoton ionization time-of-flight (REMPI-TOF) and interpreted using a d irect excitation and collisional relaxation model. There are three translat ional energy components denoted as collisionless, intermediate, and thermal ized. The collisionless component has characteristics matching those found for gas phase monomer photolysis. The thermalized component has characteris tics expected for NO accommodated to the substrate temperature, while the m ore complex intermediate component is qualitatively describable in terms of collisions of nascent energetic NO with surrounding species as it exits in to the gas phase. There are strong v " = 1 and 2 but negligible v " = 0 con tributions to the collisionless component. The collisionless component is a lso characterized by high rotational excitation; Gaussian rotational distri butions with J(max) = 24.5 +/- 1 for v " = 1 and 29.5 +/- 1 for v " = 2 pro vide reasonable fits. The translationally thermalized component is dominate d by the v " = 0 vibrational state and by a Boltzmann rotational distributi on (T-rot = 124 +/- 30 K); i.e., all three modes of motion are thermalized. The vibrational and rotational characteristics of the intermediate transla tional component are more complex and will require simulation and angle-res olved REMPI for fuller elucidation.