利用雷射光解—雷射誘發螢光技術研究氰基與亞氨基反應之動力學

Abstract

本研究利用雷射光解(laser photolysis) / 雷射誘發螢光(laser-induced fluorescence)技術偵測 NCN 及 NH 並配合電腦模擬程式Facsimile 在270–470 Torr 之 He 及210–420 Torr 之 N2 中測量NH + CN → NCN + H 反應之速率常數值。結果顯示此反應在298 K 之速率常數值隨著壓力的上升而變小，如下表：

P(He)Torr k1/10^-12 (cm^3/molecule × s) -------------------------------------------- 270 5.87±2.08 335 5.88±1.44 350 4.35±1.90 435 5.63±3.64 470 3.99±2.88

P(N2)Torr k1/10^-12 (cm^3/molecule × s) -------------------------------------------- 210 4.38±1.14 300 3.94±1.00 420 1.88±1.38

我們由模擬所觀察到的NH 自由基的衰減亦得到此反應之另一條路徑 NH + CN → CH + N2 的反應速率常數為3.0 × 10^-11 cm^3/molecule × s。

The kinetics of the CN + NH → NCN + H reaction has been studied at 298 K in 270 to 470 torr of He and in 210 to 420 torr of N2 by means of the laser photolysis / laser-induced fluorescence technique coupled with computer simulations. By simulating the observed temporal profiles of [NCN], we found that the rate constants are pressure-dependant and decrease with increasing pressure：

P(He)Torr k1/10^-12 (cm^3/molecule × s) -------------------------------------------- 270 5.87±2.08 335 5.88±1.44 350 4.35±1.90 435 5.63±3.64 470 3.99±2.88

P(N2)Torr k1/10^-12 (cm^3/molecule × s) -------------------------------------------- 210 4.38±1.14 300 3.94±1.00 420 1.88±1.38

We have also monitored the decay of the NH radicals and obtained the rate constant for CN + NH → CH + N2 channel as 3.0 × 10^-11 cm^3/molecule × s.