Physical Chemistry: Quantum Chemistry and Spectroscopy

Citation

Engel, T., & Reid, P. (2018). Physical Chemistry: Quantum Chemistry and Spectroscopy (4th ed.). Pearson.

Chapter Summary

This is the quantum-mechanics and spectroscopy volume of a two-volume physical chemistry course; the companion volume covers thermodynamics, statistical thermodynamics and kinetics. Pearson lists 17 chapters. The publisher's description credits Warren Hehre with the chapter on computational chemistry, and the preface credits co-author Alex Angerhofer with a significant contribution to the rewritten NMR chapter. Every chapter opens with three questions and responses, carries margin notes for 10–15 key concepts, and ends with a Key Equations table, further reading and problems.

Chapters 1–3: From Classical to Quantum Mechanics; The Schrödinger Equation; The Quantum-Mechanical Postulates

The opening chapters move from the classical picture to the quantum one, introduce the Schrödinger equation, and set out the postulates on which the rest of the book rests.

Chapters 4–6: Applying Quantum-Mechanical Principles to Simple Systems; Applying the Particle in the Box Model to Real-World Topics; Commuting and Noncommuting Operators and the Surprising Consequences of Entanglement

Simple model systems are solved, and the particle in a box is then applied to real-world topics; the preface notes that Section 5.4 was revised to explain conduction in solids better. Chapter 6 treats commuting and noncommuting operators and entanglement, and its Section 6.6 was extensively revised to take account of advances in quantum computing.

Chapters 7–8: A Quantum-Mechanical Model for the Vibration and Rotation of Molecules; Vibrational and Rotational Spectroscopy of Diatomic Molecules

A model for molecular vibration and rotation is followed by the spectroscopy of diatomic molecules. The preface says Section 8.4, on the origin of selection rules, was revised and expanded.

Chapters 9–11: The Hydrogen Atom; Many-Electron Atoms; Quantum States for Many-Electron Atoms and Atomic Spectroscopy

The treatment of atoms starts with hydrogen, moves to many-electron atoms, and ends with the quantum states of many-electron atoms and atomic spectroscopy.

Chapters 12–14: The Chemical Bond in Diatomic Molecules; Molecular Structure and Energy Levels for Polyatomic Molecules; Electronic Spectroscopy

Chemical bonding is treated first for diatomic and then for polyatomic molecules. Chapter 14 covers electronic spectroscopy; the preface reports that Sections 14.5, 14.7 and 14.10 were reformulated to relate electronic transitions to the molecular orbitals of the initial and final states, and Section 14.12 was revised to reflect advances in applying FRET.

Chapters 15–17: Computational Chemistry; Molecular Symmetry and an Introduction to Group Theory; Nuclear Magnetic Resonance Spectroscopy

A distinct chapter on computational chemistry, then molecular symmetry and group theory. The final chapter, on NMR, was completely rewritten and expanded in this edition, and now covers the nuclear Overhauser effect, dynamic nuclear polarization and an extensive discussion of how two-dimensional NMR is used to determine the structure of macromolecules in solution.

Key Concepts

Chapters 1–6: Foundations of quantum mechanics

• Schrödinger equation and postulates: the equation of motion for quantum systems and the rules for extracting measurable quantities (Chapters 2–3).
• Particle in a box: a simple model applied to real-world topics, including conduction in solids (Chapters 4–5).
• Commuting and noncommuting operators; entanglement: operators whose order matters, and the consequences of entanglement, including its bearing on quantum computing (Chapter 6).

Chapters 7–11: Vibration, rotation and atoms

• Vibration and rotation of molecules: the quantum model and its spectroscopic consequences, including selection rules (Chapters 7–8).
• Hydrogen atom and many-electron atoms: the quantum treatment of atoms and atomic spectroscopy (Chapters 9–11).

Chapters 12–17: Molecules, spectroscopy and calculation

• Chemical bond and molecular energy levels: bonding in diatomic and polyatomic molecules (Chapters 12–13).
• Electronic spectroscopy: electronic transitions related to molecular orbitals (Chapter 14).
• Computational chemistry, symmetry and group theory: calculating molecular structure and classifying states by symmetry (Chapters 15–16).
• NMR spectroscopy: from the basic method to two-dimensional techniques for macromolecules (Chapter 17).

Critical Analysis

Strengths

• Core concepts over encyclopedic coverage. The preface states that the aim is to build a solid understanding of a limited number of areas rather than provide a condensed encyclopedia of physical chemistry, and that the book does not have to be read in order or in full: supplemental sections can be omitted and many sections are self-contained.
• Help with the mathematics where it is needed. The third-edition math supplement was split into eleven Math Essentials of two to five pages, inserted just before the skills are required, because the authors observe that students find it hard to transfer skills from a mathematics course to physical chemistry.
• Study aids built into every chapter. The preface and publisher page list the three opening questions with responses, 10–15 marginal Concepts and Connections per chapter, a Key Equations table at the end of each chapter, Further Reading lists, worked examples, and end-of-chapter conceptual questions, numerical problems organized by section, and problems based on web simulations.
• Modern applications. The authors tie fundamentals to scanning tunnelling microscopy, quantum dots, quantum computing, band structure of solids, atomic force microscopy and NMR imaging, and the publisher highlights applications from biology, environmental science and materials science.
• A dedicated computational chemistry chapter. The publisher presents Chapter 15 as moving the teaching of bonding and molecular structure from qualitative to quantitative.

Limitations

• Only half of the physical chemistry course. The thermodynamic and kinetic material is in the companion volume, so a course covering both needs two books; the publisher notes that the Pearson+ eText of the companion volume includes the quantum chemistry and spectroscopy chapters.
• Some support sits on a separate platform. The publisher says detailed instructions for the computational problems are in Mastering Chemistry, which is sold separately; readers using only the book will not have them.
• Mathematical demands. Despite the Math Essentials, the book includes chapters on operators, group theory and two-dimensional NMR, which call for confident calculus and benefit from some linear algebra.
• Spectroscopy through theory. Spectroscopy appears through its quantum-mechanical basis (Chapters 8, 11, 14 and 17). The chapter titles do not suggest training in interpreting spectra to identify organic compounds, for which a dedicated spectral-interpretation book is better.

Where It Fits in the Course

Engel and Reid is the standard-course text in this list: a full undergraduate treatment of quantum chemistry followed by the main molecular spectroscopies. Thakkar's Quantum Chemistry: A Concise Introduction is described as a short, idea-centred introduction for readers who will use spectroscopy and electronic-structure calculations rather than develop the theory, and is a gentler first read before Engel and Reid's Chapters 1–4 and 12–13. McQuarrie's Quantum Chemistry is described as a rigorous account of the quantum ideas behind atomic structure, bonding and spectroscopy, and is the more rigorous option.

Jensen's Introduction to Computational Chemistry is the natural continuation of Chapter 15 and the computational problems. Pavia, Lampman, Kriz and Vyvyan's Introduction to Spectroscopy and Silverstein and colleagues' Spectrometric Identification of Organic Compounds concentrate on interpreting IR, NMR, UV–visible and mass spectra to find organic structures, so they complement the theory behind vibrational, electronic and NMR spectroscopy in Engel and Reid's Chapters 8, 14 and 17.

How to Use This Book

The preface identifies the target audience as undergraduates majoring in chemistry, biochemistry and chemical engineering, together with many students in atmospheric and biological sciences. It does not list formal prerequisites; the Math Essentials refresh specific mathematical skills just before they are needed.

A practical plan for a one-semester course:

• Core: Chapters 1–4 for the quantum-mechanical framework; Chapters 7–8 for vibration, rotation and diatomic spectroscopy; Chapters 9–10 for atoms; Chapters 12–14 for bonding and electronic spectroscopy.
• Selected topics: Chapters 5 and 6 (applications of the particle in a box, operators and entanglement) according to interest; Chapter 11 on atomic states if atomic spectroscopy is in the syllabus.
• Tools and extensions: Chapter 15 on computational chemistry, taken alongside Chapters 12–13; Chapter 16 on symmetry and group theory; Chapter 17 on NMR, rewritten in this edition, if NMR is on the syllabus.

Read the opening questions and the Concepts and Connections notes first, work the worked examples before the end-of-chapter problems, and use the Key Equations table for revision. Since the preface states that the book need not be read straight through, drop supplemental sections if time is short.