We have attempted to improve and update this text while retaining the features that
make it unique, namely, an emphasis on physical understanding, and the ability to
estimate, evaluate, and predict results without blind reliance on computers, while still
maintaining rigorous connection to the mathematical basis for quantum chemistry. We
have inserted into most chapters examples that allow important points to be emphasized,
clarified, or extended. This has enabled us to keep intact most of the conceptual
development familiar to past users. In addition, many of the chapters now include
multiple choice questions that students are invited to solve in their heads. This is not
because we think that instructors will be using such questions. Rather it is because we
find that such questions permit us to highlight some of the definitions or conclusions
that students often find most confusing far more quickly and effectively than we can
by using traditional problems. Of course, we have also sought to update material
on computational methods, since these are changing rapidly as the field of quantum
chemistry matures.
This book is writte