Introduction to Quantum Mechanics with Applications to Chemistry

How would an "Introduction to Philosophy" by Socrates or a "Basics of the Piano" by Mozart sound like? This is something similar. Linus Pauling, the unprecedented pioneer of the application of Quantum Mechanics to Chemistry, had written this book in the 1930s as perhaps the first introduction to QM for Chemists, supported by his colleague, E Bright Wilson, a brilliant chemist in his own right. A generation of Chemists grew up learning from this book, and its content is as relevant and articulate today as it was then. Hundreds of Quantum Chemistry books, some of which are excellent, have been written in the times since it was first published. But this book still retains an incomparable flavour that brings out the fundamental nature of QM and Chemical Bonding. I have to admit that I found this book slightly difficult, because Pauling and Wilson, although being extremely lucid, never compromise on the Math. But gradually I learnt that this is the kind of book which belongs in the same category of, say, Ernest Eliel's stereochemistry book. That means that every moment you spent on it will be worth it, even if it takes you a very long time to go through it. This is one of those books where every word is carefully thought and then stated, making the journey difficult at places, but always rewarding. And why not. It is hard to imagine anyone else writing with so much confidence on the topic. So it is important not to gloss over this book quickly and then discard it as being dry, but persist in reading it and get insight out of it. The book opens with a discussion of Lagrangian mechanics and discusses some simple examples of its applications. It then moves on to the basic principles of QM, and comes to the Hydrogen molecule, which was the pinnacle of succcess for the Physicists. I think that this book has the best discussion of the H molecule ever written. I have seen other excellent Quantum Chemistry books giving a reference to this work whenever they discuss the H molecule. Moreover, I believe that a thorough understanding of the H molecule is of paramount importance for understanding any further application of QM to Chemistry. Discussion of this molecule opens the door to understanding orbitals, spherical harmonics, angular momentum and all the important concepts in theoretical Chemistry. So the book will score top points for this alone. Later on there are excellent discussions of the Variational Method, Perturbation theory and finally the various important approximations like Hartree-Fock theory and the structure of molecules. The appendices deal with detailed discussions of derivation and some mathematical topics. All in all, a clear and extremely lucid presentation, well worth every moment you can spend on it, by one of the greatest scientists of all time.

In many ways, this is still my favourite quantum mechanics text. Why? Because the text is completely grounded in the quantum mechanics of atoms and molecules. Historically, Linus Pauling spent his post-doc working throughout Europe where he absorbed the, then, new theory of quantum mechanics. However, the physicists that he learnt q.m. from only analysed the physics of, relatively simple, atomic systems. It would require someone with an immense breadth of knowledge in chemistry to make quantum mechanics come alive for molecules. This was Linus Pauling. Pauling first applied q.m. to such diverse topics as: the chemical bond, resonance energy, electronegativity, crystal structure of molecules and hydrogen bonds. And it shows. The uniqueness of this q.m. textbook is that it gives immensely detailed references to the different ways the early physicists/chemists attacked the q.m. of bonds in molecules. Many different ansatz's and approximations to pertubation problems are given. And Pauling should know, for he was right in the thick of it. The historical value of these references alone is worth the price of this book. It's a real shame that most modern books leave these out, because a discussion of these approximations methods give a lot of insight to q.m. in molecules.In contrast, I find modern textbooks on physical chemistry to be often lacking in deep physical insight. However, textbooks written by physicists run into all sorts of esoteric directions like quantum entanglement and the uncertainty principle and as a previous reviewer noted, Pauling's books says nothing about scattering and hardly anything on spin. This is probably because chemists aren't interested in what happens to particles in beams or Stern-Gerlach experiments. They are more interested in ionisation energy, enthalpies and bond energies.Nevertheless, for out-and-out modern-day quantum physicists, Pauling's explanation of aspects of quantum mechanics will seem quaint, overly pictorial and concrete, e.g. discussion of *actual* orbits. And it is. However, for chemists and even atomic physicists, pondering such esoteric questions clouds the immense power of quantum mechanics in explaining the detailed properties of atoms and molecules.

Pauling and Wilson's introduction to quantum mechanics is an excellent text for students of quantum chemistry, and students of physics who are interested in the details of molecular wave-functions and perturbation techniques for extracting such wave-functions.There is also a chapter devoted to "old quantum theory," which students of history of science may find interesting. In it, Pauling describes some incipient theories which predate QM, such as elliptical orbit corrections to the putative hydrogen electron orbit, the Wilson-Sommerfeld quantization rules and its apparently successful application to hydrogenic atomic spectra, particle in a box, and the rigid rotator. A primer on classical mechanics and the Hamiltonian formulation is included, as is the standard wave mechanics treatment of basic quantum mechanics: Schrodinger's wave eqn, harmonic oscillator, hydrogen atom, etc. This exposition was clear. Where the book shines is its several chapters on techniques of perturbation theory, and multi-particle theory. Pauling presents virtually step-by-step calculations, showing clearly what sorts of tricks and techniques one uses to calculate certain integrals, and what coordinate systems are appropriate for particular problems (e.g. elliptical coordinates for hydrogen molecule ion.) The Slater determinant is also introduced for the generalization of the multi-particle problem. For the biophysical chemist, there is a short section on van der Waal's forces from a QM perspective. And a chapter is devoted to QM in statistical mechanics. These chapters are indispensable for the aspiring quantum chemistry student, if even just for the sake of owning something from an old master. If you're poor, you should buy this book given that it gives a big bang for the buck. If you're not poor, you should buy this book given that you're not poor.This book is extremely dense in terms of material. But that's not to say that there are a few shortcomings. The treatment of spin is not so clear- Pauling works completely in terms of wave functions and spin functions, and the reader does not have the benefits of Dirac notation in Pauling's treatment. There is also no discussion of scattering. The theoretically-minded student will also find that Pauling's treatment is lacking in explaining the deeper meanings of fundamental QM ideas, such as the commutation relations, or the time evolution of states. In short, this is not a heavily theoretical text, but rather a book of technical brilliance for applications of quantum mechanics.

Linus Pauling's treatise on quantum chemistry is even more brilliant than that on general chemistry. His vivid and clear explanation makes quantum theory so interesting and appealing to learn. Instead of going through the obscure mathematics and operator mechanics, Pauling conveys the essence of quantum mechanics in very simple language. Maybe this is how Pauling distinguishes himself as a Nobel Prize laureate. I studied Donald McQuarrie "Physical Chemistry: A Molecular Approach" (you may find my review for McQuarrie here as well) and found McQuarrie so much more understandable than Atkins. Yet Pauling's account on the subject is even more concise and motivating. The book teaches basic concepts but also ensures understanding of applied theory. While "Introduction to Quantum Mechanics" might not be as reader-friendly as its counterpart in general chemistry, I highly recommend this book for all chemistry students and those who want to adventure in advanced chemistry.

In my opinion I found this book very useful if you start studying QM, it describe in very interesting way how the modern QM theory was develop from the old one, it use simple mathematics to describe the physical phenomena compare to the other books in the same subject, and the chemistry application is something definitely you need to understand the applied theory, with this amazing low price and the material inside the book it worth every penny.