skip to main content

SciTech ConnectSciTech Connect

Title: Effect of antisymmetric C–H stretching excitation on the dynamics of O({sup 1}D) + CH{sub 4} → OH + CH{sub 3}

The effect of antisymmetric C–H stretching excitation of CH{sub 4} on the dynamics and reactivity of the O({sup 1}D) + CH{sub 4} → OH + CD{sub 3} reaction at the collision energy of 6.10 kcal/mol has been investigated using the crossed-beam and time-sliced velocity map imaging techniques. The antisymmetric C–H stretching mode excited CH{sub 4} molecule was prepared by direct infrared excitation. From the measured images of the CH{sub 3} products with the infrared laser on and off, the product translational energy and angular distributions were derived for both the ground and vibrationally excited reactions. Experimental results show that the vibrational energy of the antisymmetric stretching excited CH{sub 4} reagent is channeled exclusively into the vibrational energy of the OH co-products and, hence, the OH products from the excited-state reaction are about one vibrational quantum hotter than those from the ground-state reaction, and the product angular distributions are barely affected by the vibrational excitation of the CH{sub 4} reagent. The reactivity was found to be suppressed by the antisymmetric stretching excitation of CH{sub 4} for all observed CH{sub 3} vibrational states. The degree of suppression is different for different CH{sub 3} vibrational states: the suppression is about 40%–60% for themore » ground state and the umbrella mode excited CH{sub 3} products, while for the CH{sub 3} products with one quantum symmetric stretching mode excitation, the suppression is much less pronounced. In consequence, the vibrational state distribution of the CH{sub 3} product from the excited-state reaction is considerably different from that of the ground-state reaction.« less
Authors:
; ; ; ;  [1] ; ; ;  [1] ;  [2]
  1. State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023 (China)
  2. (China)
Publication Date:
OSTI Identifier:
22253112
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 15; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANGULAR DISTRIBUTION; COLLIDING BEAMS; COLLISIONS; EXCITATION; GROUND STATES; INHIBITION; METHANE; VIBRATIONAL STATES