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Gaussian98forWindows使用入门（待补充修改的初稿，供2001秋季学期教学试用）目录一、Gaussian98的计算功能·············································································11.1基本功能···················································································································11.2在G94基础上增加的新方法与功能··········································································2二、G98W对硬件和操作系统的要求··································································32.1硬件环境···················································································································32.2操作系统···················································································································3三、G98W的安装和软件的补钉、升级······························································33.1硬盘分区方案············································································································33.2安装软件···················································································································33.3G98W的补钉和升级·······························································································4四、G98W基本操作···························································································44.1定制软件运行时占用内存和硬盘的最大空间·····························································44.2启动程序···················································································································54.3工作环境初始化设置·································································································64.4准备计算作业的输入文件··························································································84.4.1使用ASCII文本编辑器···································································································84.4.2在“作业编辑对话框”内进行在线编辑········································································94.5运行作业···················································································································104.6用默认的外部浏览器显示分子的3D图形·································································114.7用外部文本编辑器打开输出文件阅读、分析和编辑计算结果····································12五、运用G98W的一些基本技巧········································································155.1必需的相关知识·········································································································155.1.1使用分子内坐标···············································································································155.1.2Utilities下拉菜单提供的多种功能··················································································175.1.3熟练掌握与G98W配合使用的辅助软件········································································175.2利用辅助软件构建分子和创建输入文件····································································185.2.1辅助软件与Utilities→NewMat的配合运用···································································185.2.2用Chem3D5.0pro直接创建G98W输入文件·······························································245.2.3在构建复杂的大分子时ChemDraw与Chem3D的联用················································315.3在运行作业时直接从现有检查点文件中读入Z-矩阵·················································425.4应用Utilities下拉菜单的其它功能············································································445.3.1将IR光谱计算结果传递到HyperChem进行简振模式分析··········································44（未完、待续）附录：G98W提供的主要计算功能一览······························································48•1•Gaussian98forWindows使用入门Gaussian98（以下简称G98）是一个功能强大的量子化学综合软件包。其可执行程序可在不同型号的大型计算机、超级计算机、工作站、和个人计算机上运行，并相应有不同的版本。在执行分子计算作业时，这些不同版本所使用的输入文件的核心部分的格式，包括作业控制所用的关键词、可选项代号都是一样的。其差别仅仅是输入文件Link0部位中执行作业初始化的控制语句因计算机型号而异。因此，只要在一种型号的计算机上较熟练地掌握了该软件包的使用，改用其他计算机或操作系统上的软件版本是轻而易举的事。鉴于PC机硬件技术的飞速发展和操作相当不断改进，不仅使多数量子化学计算工作可以方便地在个人计算机上进行，而且其计算速度和计算容量与工作站的差距在不断缩小。Gaussian98forWindows（以下简称G98W）与G98其它版本在同步升级，而且它可方便地与Windows平台上的具分子构建和图像显示功能的ChemOffice、HyperChem等软件结合使用，从而使得输入文件编辑和计算结果分析处理变得十分方便。目前，G98W已成为世界上被使用昀广的量子化学程序版本。对于初涉计算量子化学领域的学生和研究工作者，从G98W起步无疑是昀佳的选择。G98W提供了印刷单行本的《用户手册》（Gaussian98User’sReference）和内容几乎完全相同的的“在线帮助”功能。许多初学者犯的是不愿意查阅《手册》或在线帮助信息，而是通过别人简单指点后就急于进入研究课题所需的具体计算。以后每每遇到故障也是指赖于百问不厌。其结果往往是欲速不达，事半功倍。G98的计算功能太多，作业控制的关键词（KeyWord）和选项（Option）条目繁多。恐怕在世界上找不到任何一位专家，不需查阅手册就能对所有问题对答如流。如能熟练使用“在线帮助”将会感到比请教别人或查阅手册要方便得多。这也是学会熟练使用G98W的先决条件。本资料对入门者会有一定裨益，但绝对代替不了“在线帮助”。当你通过阅读本资料和相应的练习对G98的使用有了一知半解之后，下一步就要靠你自己的努力和钻研。NobodycanhelpYou!一、Gaussian98的计算功能1.1基本功能基本功能系指G98计算功能与其前一版本G94的相同部分。即：可执行各类不同精度和理论档次的MO计算，包括Hartree-Fock水平从头算（HF）、Post-HF从头算（各级CI和MP）、MC-SCF法、密度泛函理论（DFT），以及多种半经验量子化学方法，进行分子和化学反应性质的理论预测。主要计算项目包括：•分子的能量与几何结构•化学反应过渡态的能量与几何结构•振动频率分析•红外与拉曼光谱•分子的热化学性质•键能与化学反应能•化学反应途径•分子轨道的能量与性质•原子电荷分布（电子布居分析）和自旋密度分布•2••分子的多极矩（永久偶极矩和四极至十六极矩）•NMR屏蔽常数、化学位移及分子的磁化率•振动园二色强度（Vibrationalcirculardichroismintensities）•电子亲和性与电离势•极化率与超极化率•静电势与电子密度分布1.2在G94基础上增加的新方法与功能与G94相比，G98版本在常用功能上的昀大改进是在DFT计算上。虽然在G94中已正式引入了DFT，但其功能是不完善的，计算速度也较慢，故许多DFT用户不乐意使用。在G98版本中，Gaussian公司悄悄而又颇为圆满地解决了这些缺陷，且将迄1996年为止文献发表过的6种交换泛函、7种相关泛函以及8种交换－相关混合泛函均全部收入了程序的数据块，可方便调用。另外还引入了文献在1998年新提出的TD法（time-dependentprocedure），它可以在闭壳层基态分子的SCF-MO或DFT计算的基础上估算3个昀低的单、叁重激发态的能量（但不能修正波函数