《中国科学技术经典文库(化学卷):物质结构(第二版)》是在1959年出版的《物质结构》基础上进行修订的，作者根据当前的教学要求和化学学科的发展动向，对版内容作了较多的增删，进行了适当的调整。全书共十五章，即量子力学基础和氢原子的状态函数、原子的电子层结构和原子光谱、双原子分子的结构、分子对称性与群论初步、多原子分子的结构、共轭分子的结构、配位场理论和络合物的结构、原子价和分子结构小结、分子光谱、分子的电性和磁性、晶体结构等。书中对原子价概念的发展不仅总结了外学者的成果，并且着重介绍了作者使用（nxcπ）四个数来描述包括原子簇在内的无机和有机分子的结构类型，提出了原子价的新概念，在论述现代物质结构实验方法、原理和应用方面，除介绍IR、Raman、NMR、ESR、ESCA等主要方法外，还就如何掌握查阅、分析各种谱的数

Let'egin by discussing what the discipline of theoretical chemistry is about. I think most young students of chemistry think that theory deals with using puters to model or simulate molecular behaviors. This is only partly true. Theory indeed contains under itroad umbrella the field of putational simulations,and it is such applications of theory that have gained much recent attention especially as powerful puters and user-friendly software packages have bee widely available. However, this discipline also involves analytical theory, which deals with how the fundamental equations used to perform the simulations are derived from the Schrrdinger equation or from classical mechanics, among other things. The discipline also has to do with obtaining the equations that relate laboratory data (e.g., spectra, heat capacities, reaction cross-sections) to molecular properties(e.g., geometries, bond energies, activation energies). This analytical side ofthe0ry is also where the equations of statistical mechanics that