NEW DOUBLE-BEAM SPECTROPHOTOMETER FOR MICROSAMPLES - APPLICATION TO HYDROSTATIC-PRESSURE EXPERIMENTS

This article describes a new double beam spectrophotometer specially c onceived for optical absorption measurements on low-absorbing microsam ples. The available long-working distance makes this apparatus attract ive for use on samples placed in special environments such as heating stages, biological cells, and particularly hydrostatic pressure cells. Its performance has been tested in optical absorption measurements fo r different Mn2+ and Cu2+ complexes. We applied the instrument for inv estigating the electronic spectrum of Cu2+ doped (CH3CH2NH3)(2)CdCl4 c rystals under hydrostatic pressure using a Sapphire anvil cell. A sali ent feature of this work is the enormous redshift (1400 cm(-1)) experi enced by the first Cl- --> Cu2+ charge transfer band at 26 kbar. We br iefly comment on the origin of this shift. (C) 1995 American Institute of Physics.