case1生成焓的计算

一些热力学性质的计算统计热力学频率分析根本输出讲解反响焓的计算基于原子化反响计算生成焓的方法基于等键反响计算生成焓的方法统计热力学

频率分析根本输出讲解

计算其他温度下的热力学量：关键字中加Freq=ReadIsotopes且分子说明后添加如下内容：一些组合方法输出结果分析金标准：CCSD〔T〕外推至完备基组〔CBS〕,计算稍大体系难以实现组合方法：Gn系列G1/G2/G3/G4CBS系列CBS-APNO/CBS-Q/CBS-4W1/W2/W3/W4精度极高

反响焓的计算

HF/STO-3GC2H5H2C2H6H-77.662991-1.117505-78.306179-0.4665810.0708190.0124870.0897020.0000000.0744850.0148480.0930540.0014160.0754290.0157920.0939980.0023600.0470370.0010790.068319-0.010654-77.592179-1.105019-78.216478-0.466582-77.588513-1.102658-78.213126-0.465166-77.587569-1.101714-78.212181-0.464221-77.615961-1.116427-78.237861-0.477236

反响速率的计算

L.A.Curtiss,J.Chem.Phys.,109(1998)7764基于原子化反响的方法

实验值：-17.89kcal/mol

MP2/6-31g*CCSD/cc-pvtzB3LYP/6-31g*CBS-QB3W1G2实验值ΔfH(C,0K)0.2708800.2708800.2708800.2708800.2708800.270880

ΔfH(H,0K)0.0822780.0822780.0822780.0822780.0822780.082278

ε(C)-37.680860-37.778726-37.846280-37.785377-37.852931-37.784301

ε(H)-0.498233-0.499809-0.500273-0.499818-0.499994-0.500000

ε(CH4)+εZPE(CH4)-40.286199-40.386741-40.473175-40.409999-40.479068-40.410891

H(CH4,298K)-H(CH4,0K)0.0038030.0038110.0038080.0038150.0038160.003816

H(C,298K)-H(C,0K)0.0003980.0003980.0003980.0003980.0003980.000398

H(H,298K)-H(H,0K)0.0016100.0016100.0016100.0016100.0016100.001610

ΔfH(CH4,0K)

Hartree-0.012416-0.008789-0.025813-0.025359-0.026170-0.026599

ΔfH(CH4,298K)

Hartree-0.015450-0.011815-0.028841-0.028381-0.029191-0.029620

ΔfH(CH4,298K)

kcal/mol-9.69-7.41-18.10-17.81-18.32-18.