Surface residence time measurements of transient methyl radicals

被引:9
作者
Briggman, KA [1 ]
Stair, PC [1 ]
Weitz, E [1 ]
机构
[1] Northwestern Univ, Dept Chem, Evanston, IL 60208 USA
基金
美国国家科学基金会;
关键词
D O I
10.1016/S0009-2614(00)01448-2
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
We present the first measurement of the thermal desorption kinetics of methyl radicals. Neutral methyl radicals are photochemically produced within a methyl iodide film condensed on MgO(100). A substantial fraction become trapped through inelastic collisions with the film and thermalize to the film temperature prior to desorption. Novel residence time measurements are made by comparing neutral and ion flight times in a time-of-flight spectrometer, tin Arrhenius analysis of methyl radical residence times provides a desorption barrier of 2.5 +/- 0.5 kcal mol(-1) and a pre-factor of 10(10+/-1) s(-1). (C) 2001 Elsevier Science B.V. All rights reserved.
引用
收藏
页码:1 / 6
页数:6
相关论文
共 13 条
[1]   PHOTOFRAGMENT INVESTIGATIONS OF THE 280 NM PHOTODISSOCIATION OF METHYL-IODIDE USING REMPI I ATOM DETECTION [J].
BLACK, JF ;
POWIS, I .
CHEMICAL PHYSICS, 1988, 125 (2-3) :375-388
[2]  
BRUNS JC, 1990, THESIS NW U
[3]   Kinetic Monte Carlo studies of early surface morphology in diamond film growth by chemical vapor deposition of methyl radical [J].
Clark, MM ;
Raff, LM ;
Scott, HL .
PHYSICAL REVIEW B, 1996, 54 (08) :5914-5919
[4]   MOLECULAR-ORIENTATION AND SURFACE-MORPHOLOGY IN METHYL-IODIDE FILMS GROWN ON MGO(100) PROBED BY PHOTODISSOCIATION [J].
FAIRBROTHER, DH ;
BRIGGMAN, KA ;
STAIR, PC ;
WEITZ, E .
JOURNAL OF PHYSICAL CHEMISTRY, 1994, 98 (49) :13042-13049
[5]   Resonance enhanced multiphoton ionization/time-of-flight measurements of the velocity and internal energy content of thermal and photochemical methyl radical sources [J].
Fairbrother, DH ;
Briggman, KA ;
Dickens, KA ;
Stair, PC ;
Weitz, E .
REVIEW OF SCIENTIFIC INSTRUMENTS, 1997, 68 (05) :2031-2036
[6]   2 PHOTON RESONANCE ENHANCED MULTIPHOTON IONIZATION SPECTROSCOPY AND STATE ASSIGNMENTS OF THE METHYL RADICAL [J].
HUDGENS, JW ;
DIGIUSEPPE, TG ;
LIN, MC .
JOURNAL OF CHEMICAL PHYSICS, 1983, 79 (02) :571-582
[7]  
ITO T, 1985, J AM CHEM SOC, V107, P58
[8]   MOLECULAR ADSORPTION OF ETHANE ON THE IR(110)-(1X2) SURFACE - MONTE-CARLO SIMULATIONS AND MOLECULAR-BEAM REFLECTIVITY MEASUREMENTS [J].
KANG, HC ;
MULLINS, CB ;
WEINBERG, WH .
JOURNAL OF CHEMICAL PHYSICS, 1990, 92 (02) :1397-1406
[9]  
*MATHS INC, MATHC VERS 6
[10]   COVERAGE-DEPENDENT SURFACE-DIFFUSION OF NOBLE-GASES AND METHANE ON PT(111) [J].
MEIXNER, DL ;
GEORGE, SM .
SURFACE SCIENCE, 1993, 297 (01) :27-39