کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9637420 | 1427931 | 2005 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
The effect of temperature on collision induced intersystem crossing in the reaction of 1CH2 with H2
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: The effect of temperature on collision induced intersystem crossing in the reaction of 1CH2 with H2 The effect of temperature on collision induced intersystem crossing in the reaction of 1CH2 with H2](/preview/png/9637420.png)
چکیده انگلیسی
Laser flash photolysis of ketene at 308 nm, coupled with H atom vacuum ultraviolet laser induced fluorescence, was used to determine the branching ratio for the CH3 + H channel (1a) in the reaction of CH21A1 (1CH2) with H2, over the temperature range 300-500 K. This reaction channel competes with collision induced intersystem crossing (CIISC) to form triplet methylene, CH23B1 (3CH2) (channel 1b). The branching ratio for H formation, k1a/k1, was determined by measuring the relative H atom yield in three time resolved measurements of H: (i) in ketene, H2 mixtures, where H is exclusively formed by reaction 1a, (ii) in ketene, H2, NO mixtures ([NO] âªÂ [H2]), where H is formed at short times by 1a and at longer times by 3CH2 + NO, following 1b, and (iii) in ketene, He, NO mixtures ([NO] âªÂ [He]), where H is exclusively formed from 3CH2 + NO, following deactivation of singlet to triplet methylene by He. k1a/k1 was found to increase from 0.85 at 300 K to unity at 500 K, with the yield of CIISC decreasing from 0.15 to zero. This is the first measurement of the temperature dependence of the rate coefficient for CIISC in a reactive system. The rate coefficient for CIISC with an inert gas increases with T. It has been suggested that the fractional yield of CIISC will increase with temperature in reactive systems, thus reducing the rate coefficient for reaction at high temperature, with significant consequences for combustion systems. The present experiments demonstrate that this is not the case for reaction with H2 and implies a different CIISC mechanism for reactive vs inert collision partners.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Proceedings of the Combustion Institute - Volume 30, Issue 1, January 2005, Pages 927-933
Journal: Proceedings of the Combustion Institute - Volume 30, Issue 1, January 2005, Pages 927-933
نویسندگان
Mark A. Blitz, Namil Choi, Tamás Kovács, Paul W. Seakins, Michael J. Pilling,