Problems and Solutions
for McQuarrie's
Quantum Chemistry, Second Edition

Helen O. Leung
Mark D. Marshall
Amherst College


Preface

For as long as we have been teaching quantum chemistry, there has been Donald McQuarrie’s Quantum Chemistry, and we have both used the first edition in our classes for many years.  This solutions manual has been prepared for the second edition of Quantum Chemistry, and as Professor McQuarrie notes in his preface to the new edition, the ideas of basic quantum mechanics are timeless, but the practice of quantum mechanics has changed dramatically.  The problems and solutions contained in this manual reflect both principles.  Some of them could have been written for the very first textbooks of quantum chemistry, such as Pauling and Wilson’s 1935 text, yet are still as relevant to understanding and mastering the subject today as they were decades ago.  Other problems would have been beyond the reach of undergraduates just a few years ago, but are now routinely done using widely available software packages or the internet.

Working through problems of both types is essential to learning the ideas as well as the practice of quantum chemistry, and we hope that this solutions manual will encourage students to do many problems—perhaps even more than they are assigned!  Our own understanding of quantum mechanics continues to be enhanced as we work through problems whether they are in a textbook or come from our research laboratories.  Several times during this project Professor McQuarrie remarked to us, “I hope that you guys like doing problems. I happen to love it.”  Perhaps it is unrealistic to expect students to share this sentiment, but we hope you will at least share the satisfaction of seeing how well the basic principles of quantum mechanics work, and how they can be applied to explain so much of chemistry.

In working numerical problems, we have used the values of fundamental constants and conversion factors that appear inside the front cover of the textbook to the full precision given there.  Extra significant figures are retained in intermediate calculations with the final answer rounded to the appropriate precision.  Since this is not an introductory textbook, we occasionally depart from strict adherence to this policy if doing so helps convey an idea the problem is addressing.  Likewise, we did not think it necessary to write out explicitly the steps in every unit conversion or detail every algebraic manipulation.  We would echo Professor McQuarrie’s suggestions to learn Mathematica, MathCad, or some similar program.  Many problems that we have worked out in detail could be done straightforwardly and much faster with one or the other, and in fact, we used both to check our work.

We are grateful for the opportunity to work with Donald McQuarrie in preparing this solutions manual.  His insight, advice, and enthusiasm have been most valuable to us.  Many others helped us bring this book to print, and we wish to acknowledge their contributions.  Jane Ellis of University Science Books organized all the details, smoothed out wrinkles as they occurred, and would keep us on track if we began to drift.  Carole McQuarrie provided us with her LaTeX source for the problems.  Mervin Hanson took our graphics files and transformed them into illustrations suitable for publication.  Paul Anagnostopoulos and Jacqui Scarlott at Windfall Software endured our bad habits in LaTeX, merged the questions from the textbook into our source for the solutions, and composed the book.  Finally, they say you can best judge executives by the quality of the team they assemble, and by this measure Bruce and Kathy Armbruster are outstanding.  They are supportive and encouraging, and it is a true pleasure having them as our publishers.

And yes, Don, we love working problems, too.

Helen O. Leung
Mark D. Marshall
Amherst, Massachusetts