CHEM 334 - Quantum Chemistry & Structure of Matter - Spring 2009

INSTRUCTOR: Frank Rioux

TEXTBOOK: Quantum Chemistry and Spectroscopy by Thomas Engel

Office Hours and Teaching Schedule - Spring Semester 2009

Period\Day 1 2 3 4 5 6
I CHEM 334
ASC 135
Office Hour
ASC 241
CHEM 334
ASC 135
Office Hour
ASC 241
CHEM 334
ASC 135
Department
Meeting
II Office Hour
ASC 241

Office Hour
ASC 241

Office Hour
ASC 241
Office Hour
ASC 241
III





IV
CHEM 334
Lab
ASC 135




V
CHEM 334
Lab
ASC 135




VI
CHEM 334
Lab
ASC 135




Course Description: This course deals with the fundamental principles of quantum theory and their application to the atomic and molecular systems of interest to chemists. A major goal of CHEM 334 is to illustrate how theory and experiment work together in the development of a viable model for the nano-world of atoms and molecules. However, while the primary concern of this course is an operational mastery of fundamental principles, the rich historical and philosophical background of quantum theory will not be neglected.

There are a number of interesting quantum sites on the World Wide Web that can serve as resources for this course. They are listed below. To visit just point and click.

·  Chemistry Resources Home Page

·  A Brief Review of Quantum Chemistry

·  Quantum Chemistry in Molecular Modeling

·  Computational Chemistry and Organic Synthesis

·  University of Georgia's Center for Computational Quantum Chemistry

·  Computational Chemistry Resources

·  A Periodic Table

·  NIST Chemistry Webbook

·  NIST Physical Reference Data

·  Dan Thomas' Quantum Chemistry Course

·  Jack Simons' Theoretical Chemistry Page

·  Introduction to Quantum Computing

·  Advanced Quantum Mechanics

Many of the scientific achievements that we study in this course have earned their discoverers the Nobel Prize. There are two web sites that have extensive treatments of the contributions of the Nobel Laureates.

·  The Nobel Prize Internet Archive

·  The Nobel Foundation

·  Nobel Prizes in Chemistry

·  Nobel Prizes in Physics

The following journals frequently publish quantum mechanical articles and also contain daily updates on current advances in science. CSB|SJU has online subscriptions to both journals.

·  Science Magazine

·  Nature Magazine

Lecture: In lecture we will cover the following chapters in McQuarry and Simon. We will spend between three and four days on each chapter.

In a mathematically oriented course such as this it is extremely important that you work at it on a daily basis. This means regular attendance in class, asking lots of questions, working recommended problems at the end of the chapter, and faithfully completing the computer and spectroscopy exercises.

Your grade in CHEM 334 will be based on your performance on exams, quizzes and a cumulative final (May 7, 2008, 1:00 – 3:00 pm, ASC 135). There will be three exams and as many as five quizzes during the semester. You will be given a week's notice on exams and at least a day's notice on quizzes.

Laboratory:  The laboratory work in this course falls into two major classifications: theoretical computer exercises and analysis of spectroscopic data. The purpose of the computer exercises is to illustrate important theoretical principles and computational techniques. The emphasis in the spectroscopy labs is on the various ways that theoretical models are used to interpret the interaction of electromagnetic radiation with matter. Material covered in lab will also appear on exams and quizzes.

Lab will consist of twelve computer/spectroscopy exercises chosen from the following lists.

Computer Exercises

Spectroscopy Exercises

Naturally, you will be expected to be present for all exams, quizzes and laboratory sessions. Only under unusual circumstances will make-up exams, quizzes or labs be permitted.

Students who register CHEM 334 are charged a $90 laboratory fee. This fee is assessed to cover part of the cost of maintaining the computer laboratories, the equipment in them and the course manual you have been provided with.

Miscellaneous: The Calculus I and II prerequisites are very important for CHEM 334 because of its mathematical orientation. If you do not feel that your background in differential and integral calculus is adequate it would be advisable to spend some time reviewing these subjects early in the semester. Our textbook has a number of mini-chapters that provide mathematical support. MathChapters A, C, F, G, and H are particularly important. They deal with complex numbers, vectors, spherical coordinates, determinants, matrices, and partial differentiation.

Computer Hardware and Software: All computer labs and much of the day-to-day calculations will be done on the PCs located in Room 135 of the Ardolf Science Center. Two major software packages will be used in this course: Mathcad and Spartan. Mathcad is a high level programming environment for doing essentially all the mathematics (numerical and analytical) we will encounter in our study of quantum chemistry. We will use it on a daily basis for routine problem solving and also to do the computer labs. The first two computer labs will be devoted to an introduction to Mathcad. Approximately 75% of exam and quiz questions will be answered using Mathcad. Reference manuals for this program will be available in the Ardolf 135. Spartan is an advanced software package for doing molecular mechanics, semi-empirical and ab initio quantum mechanics on molecules of intermediate complexity. It has a powerful graphical user interface and is very easy to use. Your previous experience with Spartan in organic chemistry (and perhaps general chemistry) will be helpful.

 

Chapter 12 - From Classical to Quantum Mechanics

This introductory chapter provides historical background on the failures of classical physics and the need for a new mechanics. Among the phenomena that could not be explained classically were: black body radiation, the photo- electric effect, Compton scattering, low temperature heat capacities, atomic line spectra, and atomic and molecular stability.

Assigned problems: 1 2 3 9 11 13 14 16 17 18 19 21 22 24 25 27 29 33 35

 

Chapter 1.5 - Matrix Mechanics and Dirac Notation

There are two great traditions in quantum theory: Heisenberg's matrix mechanics and Schrödinger's wave mechanics. They are formally equivalent, but each has particular strengths in certain applications. Schrödinger's wave mechanics might be considered the default for chemists, but the basic concepts of quantum theory are probably most easily introduced via matrix mechanics.

In the early days of quantum theory Dirac introduced an elegant and powerful notation that is useful in setting up quantum mechanical calculations. After using Dirac's notation to set a calculation up, one then generally chooses either matrix or wave mechanics to complete the calculation, using that method which is most computationally friendly.

There is no Chapter 1.5 in our text. The instructor will provide several handouts which cover these areas.

Chapter 2 - The Classical Wave Equation

The Schrödinger equation is the key equation of non-relativistic quantum mechanics. It is a mathematical generalization of de Broglie's wave hypothesis for matter. De Broglie's conjecture that matter has wave-like properties and that its wavelength is inversely proportional to its momentum is the foundation of quantum mechanics. In this chapter we see that the Schrödinger equation can be derived by substituting the de Broglie wave equation into the classical wave equation.

Chapter 3 - The Schrödinger Equation and a Particle In a Box

While de Broglie's wave equation can be used directly to solve a number of simple problems, the Schrödinger equation is more general and is the basis of all computational quantum mechanics at the atomic and molecular level. In this chapter we learn how to solve Schrödinger's equation for the celebrated particle-in- the-box problem. In lab we will explore numerical solutions for Schrödinger's equation for a number of simple models.

Assigned problems: 1-6 11-14 22 24 25 27 28 33 34

Chapter 4 - Some Postulates and General Principles of Quantum Mechanics

This chapter presents the basic postulates and computational procedures of quantum mechanics. Among the key postulates of quantum theory are the assertions that the wavefunction contains all the physically meaningful information about a system and that there is an operator associated with every observable property. The postulates tell us how to obtain values for observable properties of a system from its wavefunction.

Assigned problems: 1 2 3ab 5 6-10 14 25 and additional exercises provided by instructor.

 

Chapter 5 - Harmonic Oscillator and Rigid Rotor: Two Spectroscopic Models

Schrödinger's equation is solved for the simple harmonic oscillator and the rigid rotor. Chemists use these simple concepts to model molecular vibrations and rotations in the infrared and microwave regions of the electromagnetic spectrum.

Assigned problems: 1 7-10 13-16 20 21 23 33 34 35 and additional exercises provided by instructor.

Chapter 6 - The Hydrogen Atom

Schrödinger's equation can be solved exactly for only a small number of problems. Fortunately, the hydrogen atom is among the list of exactly soluble problems. The reason this is important is that the exact solution of the hydrogen atom problem, suitably parameterized, can serve as a starting point in obtaining approximate solutions for more complicated atomic and molecular systems.

When Schrödinger's equation is solved for the hydrogen atom one obtains a set of eigenfunctions (orbitals) and associated eigenvalues (allowed energies) for the electron. This solution is in excellent agreement with the atomic line spectrum for hydrogen. Futhermore, the solutions for this one-electron problem form a basis for interpreting and understanding the chemist's periodic table.

Assigned problems: 1 5 9 11 17 18 20 21 23 24 26 27 33 39 40 41.

Chapter 7 - Approximate Methods

For most problems of interest to a chemist Schrödinger's equation does not have an exact solution. However, approximate methods are available which, under ideal circumstances, provide solutions to an arbitrary degree of accuracy. Two approximate techniques for solving Schrödinger's equation will be emphasized in this chapter and used throughout the remainder of the course - the variation method and perturbations theory.

Assigned problems: 1 2 4 5 7 8 9 10 12-15 20 21 22 25 26.

Chapter 8 - Multielectron Atoms

The Schrödinger's equation for the helium atom cannot be solved exactly, but the variational method (previous chapter) yields results in agreement with experiment. Simple variational calculations will be performed on atoms containing two, three, and four electrons. The multitude of electronic states that arise for multi-electron atoms will be analyzed by deriving atomic term symbols and comparing the theoretical results with atomic line spectra.

Assigned problems: 1-6 12 13 19 20 26-30 32 33 37 47 and additional exercises provided by instructor.

Chapter 9 - The Chemical Bond: Diatomic Molecules

The prototype in explaining atomic structure and stability was the simplest atom, the one-electron hydrogen atom. It is not surprising, therefore, that the one- electron hydrogen molecule ion, H2+, will be exploited to explain molecular stability and the physical nature of the chemical bond. In particular, the contributions of John C. Slater and Klaus Ruedenberg to our understanding of the chemical bond will be studied.

In addition to this simple molecule, the molecular orbital theory of the homonuclear diatomics from H2 to F2 and several heteronuclear diatomics will be studied.

Assigned problems: 1 9 12-19 22-28 31 38 39 41.

Chapter 10 - Bonding in Polyatomic Molecules

The use of hydrid orbitals in interpreting the bonding in polyatomic molecules is introduced. The Huckel molecular orbital approximation is used to model the pi-electrons of conjugated organic molecules. Molecular orbital theory is used to interpret the photoelectron spectroscopy of di- and tri-atomic molecules.

Assigned problems: 1 5 7 19 27-38 and additional exercises provided by instructor.

Chapter 11 - Computational Quantum Chemistry

John Pople (see page 410 of our text for a biographical sketch and picture) shared the 1998 Nobel Prize in Chemistry for his enormous contributions to the development of the field of computational quantum chemistry. While the basic principles of quantum theory have been known for 75 years it is only recently through the efforts of Pople and others that calculations on large molecules have become feasible. This has enhanced the stature of theory and made it an equal partner with experiment in contemporary chemical research. This chapter provides a concise outline of computational quantum chemistry that will provide the background necessary to appreciate the capabilities of the electronic structure program, Spartan, that we will use in lab.

Assigned problems: 2 3 4 5 8 10 11 20 24 28 and additional exercises provided by instructor.

Chapter 12 - Group Theory: The Exploitation of Symmetry

Most molecules don't have any symmetry, but for those that do group theory is a powerful analytic tool. In this chapter we learn how to classify molecules into symmetry groups. Then we will use this information plus the principles of group theory to construct molecular orbitals and to interpret the vibrational and electronic spectra of molecules. The power of group theory will be demonstrated by its application to a detailed study of the water molecule and the recently discovered new allotropic form of carbon, C60.

Assigned problems: 3-6 19 22 40-43 and additional excercises provided by instructor.

Chapter 13 - Molecular Spectroscopy

The pure rotational and vibrational-rotational spectra of simple di- and tri- atomic molecules will be studied. The rigid rotor, non-rigid rotor, harmonic oscillator, and anharmonic oscillator models will be used to interpret spectra.

Assigned problems: 1-5 7-9 14 15 18 20 22 27 30 44-48 and additional exercises provided by instructor.

Chapter 14 - Nuclear Magnetic Resonance Spectroscopy

The quantum mechanical basis of nuclear magnetic resonance will be clarified by the analysis of the nmr spectra of two ABC spin systems: acrylonitrile and vinyl acetate (the vinyl protons do not interact appreciably with the methyl protons). The high field and low field nmr spectra of both molecules will be analyzed using a variational calculation on the nuclear spin states.

Assigned problems: Will be provided by instructor.

Chapter 15 - Lasers, Laser Spectroscopy, and Photochemistry

Following a basic introduction statistical mechanics (Bolztmann, Fermi-Dirac, and Bose-Einstein) quantum mechanical principles will be used to understand the structure and operation of a laser and its spectroscopic applications.

Assigned problems: Will be provided by instructor.

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