Selection Rules in the Raman Effect

F. RASETTI

doi:10.1038/123757c0

New Developments in Raman Spectroscopy with Lasers: Electronic Transitions

Applied Spectroscopy ◽

10.1366/000370268774384597 ◽

1968 ◽

Vol 22 (5) ◽

pp. 438-444 ◽

Cited By ~ 17

Author(s):

J. A. Koningstein

Keyword(s):

Raman Spectroscopy ◽

Single Crystals ◽

Crystal Field ◽

Raman Spectra ◽

Raman Effect ◽

Electronic Transitions ◽

New Developments ◽

Selection Rules ◽

Phonon Spectra ◽

Host Lattices

A discussion is given of the Raman spectra of single crystals of yttrium gallium garnet (YGaG), of ytterbrium gallium garnet (YbGaG), and of Yb:YGaG. From a comparison of the spectra it has been possible to separate the phonon spectra of the host lattices from that of an electronic Raman effect which occurs between the crystal field levels of the 2F7/2 manifold of Yb3+ in the garnet crystals. Information with respect to the selection rules governing both types of spectra is given.

Download Full-text

Selection Rules for an Electronic Raman Effect in a Situation where the Appropriate Point Group is a Double Group

Physical Review ◽

10.1103/physrev.174.477 ◽

1968 ◽

Vol 174 (2) ◽

pp. 477-478 ◽

Cited By ~ 16

Author(s):

J. A. Koningstein

Keyword(s):

Raman Effect ◽

Point Group ◽

Selection Rules ◽

Double Group

Download Full-text

The discovery of the Raman effect

Notes and Records the Royal Society journal of the history of science ◽

10.1098/rsnr.1989.0001 ◽

1989 ◽

Vol 43 (1) ◽

pp. 1-23 ◽

Cited By ~ 2

Keyword(s):

Raman Effect ◽

Rapid Development ◽

Building Blocks ◽

Incident Radiation ◽

100Th Anniversary ◽

Polyatomic Molecules ◽

Transparent Medium ◽

Selection Rules ◽

Absorption And Emission ◽

The World

C. V. Raman was born on 7 November 1888. A 100th anniversary • is a milepost, an occasion on which to review the best known of his contributions to science: the recognition that light scattered from a transparent medium includes wavelengths shifted from that of the incident radiation. It was realized from the outset that these shifts were due to an interaction, subtly different from the ordinary processes of absorption and emission, involving exchange of energy between radiation and the molecules of the medium. The discovery was promptly christened the Raman effect by Pringsheim (1), a phrase that caught on immediately and survives today. Its announcement in 1928 drew the attention of scientists around the world and ushered in a period of rapid development that brought the new spectroscopy onto a plateau where it remained, with few changes of substance, for practically a quarter of a century. For most purposes the experimental procedures were easily adapted from tried and true methods already in place for measurement of fluorescence: such instruments were put together from basic building blocks and examples already existed in a number of laboratories. The necessary theory, including selection rules and related symmetry considerations, emerged more gradually and several years elapsed before their framework was firmly in place. To some extent, however, this delay could be attributed to the greater attention now given to polyatomic molecules whose spectra had not been seriously addressed in the older forms of spectroscopy.

Download Full-text

SELECTION RULES AND TEMPERATURE DEPENDENCE OF THE FIRST-ORDER RAMAN EFFECT IN CRYSTALS

Canadian Journal of Physics ◽

10.1139/p56-035 ◽

1956 ◽

Vol 34 (3) ◽

pp. 312-338 ◽

Cited By ~ 11

Author(s):

O. Theimer

Keyword(s):

Temperature Dependence ◽

Raman Effect ◽

Scattered Light ◽

Low Frequency ◽

Current Theory ◽

Selection Rules ◽

First Order ◽

Non Linear ◽

Full Symmetry ◽

Linear Effects

Starting from the most general scattering formulae, the current theory of the Raman effect in crystals is modified in such a way as to remove the well-known discrepancies between theory and experiment concerning the selection rules for calcite and similar crystals. A distinction is made between electrons in delocalized crystal orbitals and electrons in localized atomic or molecular orbitals and it is shown that only the latter produce a Raman scattering in agreement with the unmodified theory. The general formula for the scattering by delocalized electrons is analyzed and it is found that the magnitude of the components [Formula: see text] of the first-order polarizability (qi normal coordinate of the scattering lattice vibration) depends on the wave vectors Q′ and Q″ of incident and scattered light. The wave vector dependence of the first-order polarizability requires selection rules for the first-order Raman effect which do not correspond to the full symmetry of the scattering crystal but only to the symmetry operations of the group of Q = Q′ – Q″ which leave Q unchanged. These modified selection rules are shown to be compatible with experiment. The influence of mechanical anharmonicity and of polarizability derivatives of higher order on the first-order Raman effect is also discussed. It is found that these non-linear effects offer no satisfactory explanation for the great intensity of forbidden lines in the Raman spectrum of some crystals. Concerning temperature effects the non-linear terms in the intensity formulae are found to be of greater importance and are tentatively suggested as being responsible for the anomalous temperature dependence of low frequency external lattice vibrations.

Download Full-text