CHEM2301: Physical Chemistry

Course Organizer: Dr Simon T. Banks

Lecturers: Dr K Holt, Dr D J Caruana, Dr Simon T. Banks, Prof N Kaltsoyannis, Dr D M Rowley

Normal prerequisite: CHEM1301

Units: 1

Aims

The aims of this course are to develop further quantum mechanics and thermodynamics and to extend the material of CHEM1301 to spectroscopy, kinetics, and electrochemistry.

Objectives

Students will be able to

  • apply the fundamental postulates of quantum mechanics to problems with exact and approximate solutions
  • use molecular orbital theory with diatomic molecules and Hückel theory with p electron systems
  • apply the second law of thermodynamics to homogeneous and heterogeneous systems
  • apply thermodynamics to phase equilibria and chemical equilibria
  • understand electrochemical systems in terms of simple electroyte theory
  • use the stationary state approximation to study unimolecular, linear and branched chain reactions
  • analyse chemical systems using atomic, rotational, vibrational and electronic spectroscopy
  • discuss the fates of electronically excited molecules

Course Structure

  • Lectures: 45
  • Tutorials: 20
  • Labs: 5 afternoons

Assessment

  • Exam: 70% (3 hours)
  • Lab: 20%
  • Coursework: 10%

Practical course organizer:

Dr S T Banks

Recommended Texts

  • R Silbey, R A Alberty and M G Bawendi Physical Chemistry 4th Edition John Wiley. Earlier editions of Ailbey and Alberty are equally useful.

An acceptable alternative is:

  • P W Atkins and J de Paula Atkins' Physical Chemistry 8th edition, Oxford 2006; or earlier editions

Further Reading

  • M L McGlashan, "Chemical Thermodynamics", 2nd ed, Academic Press
  • I N Levine, "Quantum Chemistry", 4th ed, Prentice Hall, 1991
  • J M Hollas, Modern Spectroscopy", 2nd ed, Wiley, 1992
  • A Gilbert and J Baggott, "Essentials of Molecular Photochemistry", Blackwells,1991

Course Outline

Quantum Mechanics NK, 9 lectures

  • Fundamental principles and postulates: probability interpretation of Ψ, operators and Hamiltonians, eigenvalue equations, Schrödinger equation, expectation values, Variation principle, more dimensions and particles.
  • Exact solutions to the Schrödinger equation: harmonic oscillator, particle on a ring, particle on a sphere (rigid rotor), hydrogen atom.
  • Beyond exact solutions: helium atom.
  • Molecular orbitals: Born-Oppenheimer approximation, linear combination of atomic orbitals, secular equations, two-orbital systems.
  • Hückel theory for π‑electron systems.

Thermodynamics STB, 9 lectures

  • The second law of thermodynamics is introduced and its application to chemical systems is developed.
  • Equilibrium: thermal, hydrostatic, diffusive, and chemical.
  • Revision of the first law from CHEM1301: calorimetry; flow calorimetry of gases; isothermal and isenthalpic Joule Thomson coefficients and heat capacity.
  • Partial differentiation; importance of T and p , as variables.
  • Equalities of the second law of thermodynamics; thermodynamic surfaces; Gibbs and Helmholtz energies; entropy, Maxwell equations; variation of T and p ; Gibbs-Helmholtz equation; van't Hoff equation; integrated second-law equations; Gibbs-Duhem equation.
  • Homogeneous systems: use of integrals to determine the change in state of a phase. Gas expansions: isenthalpic and isentropic; liquefaction of gases;differences in heat capacities and compressibilities; the speed of sound.
  • Heterogeneous systems: densities and fields; applications of the Gibbs-Duhem equation; phase equilibrium; vapour pressure and the Clapeyron equation, Trouton's rule.
  • Tabulated thermodynamic data, calculation of equilibrium constants.

Kinetics, Photochemistry and Atmospheric Chemistry DMR, 9 lectures

  • Gas-phase kinetics: stationary state approximation; unimolecular reactions; Lindemann mechanism; introduction to RRKM theory.
  • Linear chain reactions: classification of elementary steps; pyrolysis of ethanal and ethane.
  • Excitation and the fate of electronically excited states of molecules; fluorescence, phosphorescence, non-radiative processes, vibrational relaxation, Stokes shift, dissociation, predissociation, quenching.

Spectroscopy KH, 9 lectures

  • Atomic Spectroscopy: The H atom, term symbols, selection rules, absorption and emission spectra for Na, the Helium atom, spectra of many electron atoms.
  • Molecular Spectroscopy: Born-Oppenheimer approximation, experimental techniques, rotational spectroscopy: selection rules, energy level expressions, intensities, centrifugal distortion, deriving bond lengths.
  • Vibrational Spectroscopy: harmonic and anharmonic oscillators, selection rules, force constants, vibration-rotation spectra, dissociation energies, hot bands.

Solutions and Electrolyte Solutions DJC, 9 lectures

  • Ideal solutions, non-ideal solutions. Henry's law and Raoult's law. Coligative properties in general. Electrolyte solutions. Columbic interactions, deviations from ideal behaviour.
  • Debye Hiickel model for electrolyte solutions of Derivation of limiting law. Conductivity of electrolye solutions. Molar conductivity, strong and weak electrolytes. Onsanger equation. Kohlrausch's Law, Grotthus mechanism. Transport numbers.
  • Electrochemical potential. Electrochemical cells. Standard electrode reactions. The standard hydrogen electrode. Nernst equation. Electrochemical redox reactions, Half cell reactions. Overall cell reactions. Measurement of emf. Cell potential convention.
  • Thermodynamics of electrode/solution interface. Conventional representation of electrochemical cells. Liquid Junctions and salt bridges. Electrochemical double layer parallels with the Debye Hiickel model. Electrode reactions.