DifferentiaI PoIarization Spectroscopy on Single Crystals of Transition Metal Complexes

Abstract

In the last decade there has been a growing interest in phase modulation spectroscopy of general anisotropic media due to the fact that the piezoelectric (photoelastic) modulator, described in 1969 by Kemp [1], features the possibility of changing a spectrophotometer from the “circular dichroism mode” (CD) into the “linear dichroism mode” (LD) without any alterations in the lightpath, but only through a change of the electronic system composing the spectrophotometer [2–4]. This contrasts with situations in which a Pockels cell is used as the modulator [5]. The instrumental set-up of this type of instrument is fixed to such an extent that fairly drastic changes have to be introduced in the optical path in order to convert the machine from a circular into a linear dichrograph [6–8].