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yuwenxianglong

铁杆木虫 (正式写手)


[资源] Thermochemistry in Gaussian

Joseph W. Ochterski, Ph.D.
help@gaussian.com

c 2000, Gaussian, Inc.
June 2, 2000

The purpose of this paper is to explain how various thermochemical values are computed in Gaussian. The paper documents what equations are used to calculate the quantities, but doesn't explain them in great detail, so a basic understanding of statistical mechanics concepts, such as partition functions, is assumed. Gaussian thermochemistry output is explained, and a couple of examples, including calculating the enthalpy and Gibbs free energy for a reaction, the heat of formation of a molecule and absolute rates of reaction are worked out.


Contents
1 Introduction 2
2 Sources of components for thermodynamic quantities 2
2.1 Contributions from translation . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 Contributions from electronic motion . . . . . . . . . . . . . . . . . . . . . . 4
2.3 Contributions from rotational motion . . . . . . . . . . . . . . . . . . . . . . 4
2.4 Contributions from vibrational motion . . . . . . . . . . . . . . . . . . . . . 6
3 Thermochemistry output from Gaussian 8
3.1 Output from a frequency calculation . . . . . . . . . . . . . . . . . . . . . . 8
3.2 Output from compound model chemistries . . . . . . . . . . . . . . . . . . . 11
4 Worked-out Examples 11
4.1 Enthalpies and Free Energies of Reaction . . . . . . . . . . . . . . . . . . . . 12
4.2 Rates of Reaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.3 Enthalpies and Free Energies of Formation . . . . . . . . . . . . . . . . . . . 14
5 Summary 17
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好好生活

木虫 (著名写手)


★★★ 三星级,支持鼓励

怎么没什么人看啊,给点支持吧
4楼2007-10-23 08:31:22
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phychemlxd

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LZ,具体算过生成热吗?用的是什么方法,G3是不是经常算不下去?我前两天打算算过含苯环和硝基的物质,老是跳出来。给点意见
3楼2007-02-04 16:10:14
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