利用理論計算方法探討HCCN自由基和NO之反應機制與RRKM理論預測反應速率常數

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Title:	利用理論計算方法探討HCCN自由基和NO之反應機制與RRKM理論預測反應速率常數
Authors:	趙婉君
Contributors:	應用化學研究所
Keywords:	初始法 Fukui functions 硬軟酸鹼理論
Date:	2010
Issue Date:	2011-11-14 15:00:45 (UTC+8)
Abstract:	我們使用高層級的初始法（Ab initio）去研究cyanomethylene radical（HCCN）與NO的反應機構與動力學分析。我們使用B3LYP/6-311++G(3df,2p)做結構最佳化，單點能量則使用CCSD(T)/aug-cc-PVQZ//B3LYP/6-311++G(3df,2p) 去計算。我們預測並計算所有的結構去找出最適當的路徑，在我們的所有路徑當中，以產生P1（HCN + NCO）與P3（HCNO + CN）兩種產物為主要路徑。經由Fukui functions以及硬軟酸鹼理論（HSAB）可以去合理地解釋我們所計算出來的結果。所預測的速率常數( ktotal )於760 torr Ar pressure下可以從方程式中得到:當溫度介於298–3000 K時 ktotal = 1.40×10-7 T-2.01 exp(3.15 kcal mol-1/RT )，單位為cm3 molecule-1 s-1。除此之外，在實驗上有觀察到在18與30 torr下，關於HCCN+NO預測之速率常數可以提供我們作進一步比較我們可以利用不同的溫度與壓力之條件計算其速率常數並列在表中，可以作為未來燃燒化學的應用。 High level ab initio calculations have been performed to study the mechanism and kinetics of the reaction of the cyanomethylene radical (HCCN) with the NO. The species involved have been optimized at the B3LYP/6-311++G(3df,2p) level and their corresponding single-point energies are improved by the CCSD(T)/aug-cc-PVQZ// B3LYP/6-311++G(3df,2p) approach. From the calculated potential energy surface, we have predicted that that the favorable pathways for the formation of several isomers of an HCCNNO complex. Formations of HCN + NCO (P1) and HCNO + CN (P3) are also probable, although these two pathways require little thermal activation. To rationalize the scenario of our calculated results, we also employ the Fukui functions and HSAB theory to seek the possible clues. The predicted total rate coefficient, ktotal, at He pressure 760 torr can be represented with an equation: ktotal = 1.40×10-7 T-2.01 exp(3.15 kcal mol-1/RT) at T = 298–3000 K, in units of cm3 molecule-1 s-1. The predicted total rate coefficients at some available conditions (18 and 30 torr) are in good agreement with experimental observation. In addition, the rate constants for key individual product channels are provided in different temperature and pressure conditions.
Appears in Collections:	[Department of Chemistry & Graduate Institute of Applied Chemistry ] thesis

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謝誌.pdf	227Kb	Adobe PDF	341	View/Open
摘要.pdf	273Kb	Adobe PDF	243	View/Open
目錄.pdf	256Kb	Adobe PDF	250	View/Open
chp1.pdf	229Kb	Adobe PDF	265	View/Open
chp2.pdf	573Kb	Adobe PDF	7962	View/Open
chp3.pdf	2518Kb	Adobe PDF	800	View/Open
chp4.pdf	251Kb	Adobe PDF	210	View/Open
ref.pdf	303Kb	Adobe PDF	382	View/Open
附錄.pdf	1043Kb	Adobe PDF	601	View/Open

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