Pure rotational Raman spectra of the chlorine species, 35Cl2 and 35Cl37Cl

Abstract

The rotational constants and bond lengths of ³⁵Cl₂ and ³⁵Cl³⁷Cl have been redetermined from the photographically-recorded pure rotational Raman spectra. For ³⁵Cl₂ the precision of the results equals that of the best values obtained from the visible absorption spectrum; for ³⁵Cl³⁷Cl the precision of the present result is much greater than that of the only previous determination. Using α-values for ³⁵Cl₂ and ³⁵Cl³⁷Cl derived from electronic spectroscopy, B_e, and hence r_e, values have also been Calculated. Combining the present results with the best electronic spectroscopy results gives for ³⁵Cl₂ the weighted mean bond lengths; r₀= 1.991 0 ± 0.000 2 Å(1 Å= 100 pm) and r_e= 1.988 2 ± 0.000 2 Å. For ³⁵Cl³⁷Cl the present work gives r₀= 1.991 7 ± 0.000 5 Å and r_e= 1.988 6 ± 0.000 5 Å.