THE COPPER TRIMER AND ITS ARGON VAN-DER-WAALS COMPLEX - AN ANOMALOUS SHIFT IN THE (A)OVER-TILDE[-(X)OVER-TILDE PHOTODISSOCIATION SPECTRUM

The photodissociation spectra of Cu-3 and Cu3Ar have been recorded fro m 500 nm to 550 nm. The spectrum of Cu-3 shows a number of resolved vi bronic bands in 522-538 nm range, in accord with the previous observat ions of Morse et al. [J. Chem. Phys. 79, 5316 (1983)]. By contrast, th e spectrum of Cu3Ar shows no resolved vibronic structure and is displa ced over 20 nm to the blue of the Cu-3 (A) over tilde <-- (X) over til de origin at 539.8 nm. In addition, the oscillator strength of the Cu3 Ar absorption band is a factor of six times larger than that of CU3. T hese results are discussed in light of the known photophysical and spe ctroscopic properties of CU3.