Open AccessCarbon and hydrogen kinetic isotope effects for the reaction of Cl with CH 4 : Consolidating chemical kinetics and molecular dynamics measurements
Author(s) -
Michelsen H. A.
Publication year - 2001
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2000jd900689
Subject(s) - kinetic isotope effect , kinetics , hydrogen , kinetic energy , chemical kinetics , analytical chemistry (journal) , extrapolation , chemistry , materials science , deuterium , physics , atomic physics , organic chemistry , quantum mechanics , mathematical analysis , mathematics
In order to estimate carbon and hydrogen kinetic isotope effects for the reaction Cl+ CH 4 at atmospheric temperatures, measured values of the rates of Cl reacting with 13 CH 4 , 12 CH 3 D, 12 CH 2 D 2 , 12 CHD 3 , and 12 CD 4 relative to those of Cl+ 12 CH 4 were fit using a model that accounts for quantum mechanical tunneling. The model also includes vibrational enhancement of the reaction rate by excitation of the bending and stretching modes of CH 4 . These fits allow extrapolation of measured values to temperatures outside the range in which they were measured. In addition, the kinetic isotope effect for Cl+ 14 CH 4 was predicted using this model based on the results for Cl+ 13 CH 4 . The model results for Cl+ 14 CH 4 , Cl+ 13 CH 4 , and Cl+ 12 CH 3 D were parameterized for use in atmospheric models.