PROBING MOLECULAR SITE STRUCTURE IN LOW-TEMPERATURE MATRICES - AN EXAFS STUDY OF CARBONYL SULFIDE IN SOLID ARGON

We present here an EXAFS (extended x-ray absorption fine structure) ex periment performed at the K edge of the sulfur atom of OCS isolated in an argon matrix. The aim was to elucidate the structure of the trappi ng site of the molecule. We show that the argon atoms are located at a mean distance of 3.78 Angstrom from the sulfur atom, with a root mean square variation of the S-Ar distances of about 0.08 Angstrom. Our re sults indicate that the host atoms occupy a statistical set of positio ns around the molecule, rather than well-defined sites. (C) 1998 Ameri can Institute of Physics. [S0021-9606(98)00442-5]