A formalism to connect first-order Raman intensities of MgF2 and its photoelastic constants is developed by developing a method of writing internal coordinates in terms of displacement gradientsuij which are not symmetric. It is found that for crystals containing only one line inA1 species, the ratiosP13/P33 and (P11 +P12)/P31 can be directly evaluated from the intensities, without having to derive the intensity formulae; while (P11 +P12)/P13 is independent of the intensities as well as the refractive index of the crystal. It is a function of only the dimensional parameters. In this crystal, since the speciesB1g andB2g also contain only one line each, the ratio (P11 −P12)/P66 can also be directly obtained from the intensities.
Volume 96, 2022
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