STUDY OF ISOTOPE EFFECTS IN THE GROUND-STATE OF THE SYMMETRICAL ISOTOPOMERS OF CUCL2

Investigations of the ground state of CuCl2 have been pursued, recordi ng laser induced fluorescence spectra on a Bomem DA3 Fourier transform spectrometer in the range 10000-16500 cm(-1). A single mode ring dye laser, set in the red (615-665 nm), excited the (IIu)-I-2-(X) over til de(2)II(g) electronic transition in copper dichloride vapour. Analysis of spectra recorded from isotopically enriched samples of CuCl2 allow ed us to check our assignment of vibrational stretching quantum number s nu(1)(less than or equal to 7) and nu(3)(less than or equal to 8) in the ground state. A normal mode model including isotope effects has b een used to fit data from all four symmetrical isotopomers of copper d ichloride. The rms deviation of the fit containing about 4000 lines is 0.040 cm(-1). From this model, we find an equilibrium Cu-Cl bond leng th of 0.203335(5) nm and force constant k(1) =277.28(1) N m(-1).