module specification

The module examines key aspects of atomic and molecular spectra arising from the absorption, emission or scattering of electromagnetic radiation. Topics include atomic spectroscopy, molecular symmetry and group theory, rotational spectroscopy, vibrational spectroscopy, electronic spectroscopy, Raman spectroscopy and laser spectroscopy. It provides an appreciation for varied applications in which spectroscopic methods are utilised for the determination of chemical structure and properties.

CY6059

Atomic Spectroscopy
Absorption and emission of radiation; line intensities and Einstein coefficients; line widths; quantum numbers; angular momenta and magnetic moments; Russell-Saunders coupling; atomic terms and states, the Zeeman effect. LO1,LO3

Experimental Methods
General experimental features of atomic and molecular spectroscopy: dispersing elements; Fourier transformation and interferometers; radiation sources; absorption cells; detectors; other experimental techniques (e.g. ATR, RAIRS, AAS, ICP-AES); typical spectrophotometer design. LO2,LO4

Molecular Symmetry and Group Theory
Symmetry operations (applied to basic shapes and molecules); point groups; character tables; symmetry and dipole moments. LO3

Rotational Spectroscopy
Essential theories and applications of rotational infrared, millimetre wave and microwave spectra: types of rotor (determined from moments of inertia); diatomic and linear polyatomic spectra; spectral intensities; centrifugal distortion; symmetric, asymmetric and spherical rotor molecular spectra; the Stark effect; interstellar molecular spectra. LO1,LO2,LO3

Vibrational Spectroscopy
Predicting and interpreting infrared spectra: diatomic IR spectra; the harmonic oscillator; vibrational selection rules; dipole and transition moments; anharmonicity and the Morse potential; dissociation energies and Birge-Sponer plots; rovibrational spectra; polyatomic molecules; group vibrations; overtones; spectral broadening; determination of normal vibrations (application of group theory). LO1,LO2,LO3,LO4

Light Scattering and the Raman Effect
Rayleigh scattering; the Raman effect; Stokes and anti-Stokes scattering; polarizability; rotational Raman spectra of diatomic and linear polyatomic molecules; selection rules; rovibrational Raman spectra; complementarity with IR spectra. LO1,LO2,LO3

Electronic Spectroscopy
Molecular orbital theory; classification of electronic states; electronic selection rules; vibronic spectra, progressions and sequences; the Franck-Condon principle; Deslandres tables; dissociation energies; rovibronic spectra; Walsh diagrams; chromophores; features of polyatomic spectra. LO1,LO3

Laser Spectroscopy
General features and properties of lasers; population inversion; cavity modes; Q-switching; mode-locking; examples of laser systems; uses of lasers in spectroscopy. LO1,LO2

Acquisition of knowledge of the subject matter will be promoted through lecturer-led lectures (16 hours), tutorials (8 hours) a problem-based workshop (3 hours), a laboratory practical (4 hours), directed web-based learning and through the guided use of student-centred learning resources. Additional exam preparation will be facilitated through a revision session (3 h). There will also be weekly drop-in sessions (1 hour), which students can make use of in order to consolidate their understanding of the subject matter.

On successful completion of this module students will be able to:
1. Use fundamental spectroscopic theory to critically analyse and interpret atomic and molecular spectra, explaining their key features and calculating related spectroscopic constants.
2. Describe and compare the experimental methods and techniques used to produce atomic and molecular spectra in a variety of applications.
3. Predict spectrally observed transitions by applying selection rules and group theory.
4. Perform experimental procedures to produce molecular spectra and critically analyse and evaluate the results.

Core text: Hollas, J. M. (2003) Modern Spectroscopy: 4th Edition, Wiley

Other texts:
Brown, J. M. (1998) Molecular Spectroscopy, Oxford Chemistry Primers, Oxford University Press
Hollas, J. M. (2002) Basic Atomic and Molecular Spectroscopy: RSC (Tutorial Chemistry Texts), Royal Society of Chemistry
Banwell, C., McCash, E. (1995) Fundamentals for Molecular Spectroscopy, McGraw-Hill Publishing
Bernath, P. F. (2005) Spectra of Atoms and Molecules: 2nd Edition, Oxford University Press
Dogge, G., Cockett, M. (2012) Maths for Chemists: 2nd Edition, Royal Society of Chemistry Publishing
Websites: Specific links to websites will be given on Weblearn including links from www.khanacademy.org

Interactive digital resources: Preparation for practical class and written practical report will be supported by interactive LearnSci resources embedded into WebLearn.