THERMAL-ISOMERIZATION IN CS4CL3-

Theoretical electronic structure studies have been carried out to show that the recently observed thermal isomerization in Cs4Cl3- clusters is due to three energetically close structures with a cuboid, a ladder , and an octagonal ring arrangement. It is found that the electronic e xcited states can serve as a fingerprint for identification of these s tructures. By calculating total energies and electronic excited states , we identify the cuboid as the most stable geometry. The vibrational spectra of the isomers are shown to be marked by low-energy modes whic h enable them to isomerize at ordinary temperatures.