This manual is intended as a general-purpose user’s guide for Q-Chem, a modern electronic structure program. The manual contains background information that describes Q-Chem methods and user-selected parameters. It is assumed that the user has some familiarity with the Unix/Linux environment, an ASCII file editor, and a basic understanding of quantum chemistry.
The manual is divided into 12 chapters and 3 appendices, which are briefly summarized below. After installing Q-Chem, and making necessary adjustments to your user account, it is recommended that particular attention be given to Chapters 3 and 4. The latter chapter has been formatted so that advanced users can quickly find the information they require, while supplying new users with a moderate level of important background information. This format has been maintained throughout the manual, and every attempt has been made to guide the user forward and backward to other relevant information so that a logical progression through this manual, while recommended, is not necessary.
Documentation for IQmol, a graphical user interface designed for use with Q-Chem, can be found on the IQmol website (www.iqmol.org). IQmol functions as a molecular structure builder, as an interface for local or remote submission of Q-Chem jobs, and as a post-calculation visualization program for densities and molecular orbitals.