Force constants of Rh2(CO)4(m-Cl)2 and Rh(m-CO)3(CO)9 were obtained on the basis of general valence force field computation. The calculated frequencies are in good agreement with the observed spectra. The strength of M-M and M-L bonds, the effects of bridging ligands on M-M stretching, and the various approx. force fields for clusters are discussed.

Key words: POLYETHYLENE, INFRARED SPECTROPHOTOMETRY, COMPUTER APPLICATIONS, CARBONYL COMPLEX, CHEMICAL BONDS, CLUSTER COMPOUND, CONFIGURATION, MOLECULAR VIBRATION, RHODIUM COMPLEX, POTASSIUM BROMIDE