Potential Constants of PCl3 from Amplitudes of Vibration and Normal Vibration Frequencies

Abstract

Using the mean square amplitudes of vibration obtained from gaseous electron diffraction experiments at 300° and 505°K together with the normal vibration frequencies, a reasonable set of values has been derived for the potential constants of the general quadratic function $${\text{2V=Σf}}_{\tau }{\mathrm{(\Delta r}}_i{)}^2{\text{+2Σf}}_{\mathrm{rr}}{\mathrm{(\Delta r}}_i{\mathrm{)(\Delta r}}_j{\mathrm{)+\Sigma f}}_{\theta }{\mathrm{(r}}_0{\mathrm{\Delta \theta }}_{\mathrm{ij}}{)}^2{\text{+2Σf}}_{\mathrm{\theta \theta }}{\mathrm{(r}}_0{\mathrm{\Delta \theta }}_{\mathrm{ij}}{\mathrm{)(r}}_0{\mathrm{\Delta \theta }}_{\mathrm{jk}}{\text{)+2Σf}}_{\mathrm{r\theta }}{\mathrm{(\Delta r}}_i{\mathrm{)(r}}_0{\mathrm{\Delta \theta }}_{\mathrm{ij}}{\text{)+2Σf}}_{\mathrm{r\theta }}^{\prime }{\mathrm{(\Delta r}}_i{\mathrm{)(r}}_0{\mathrm{\Delta \theta }}_{\mathrm{jk}}\mathrm{).}$$ The values in millidynes/A are, with estimated standard errors, $f_r{\text{=2.82}}_9{\text{±0.37}}_4{\mathrm{,f}}_{\mathrm{rr}}{\text{=0.58}}_9{\text{±0.29}}_8{\mathrm{,f}}_{\theta }{\text{=0.27}}_8{\text{±0.03}}_8{\mathrm{,f}}_{\mathrm{\theta \theta }}{\text{=0.45}}_5{\text{±0.03}}_9{\mathrm{,f}}_{\mathrm{r\theta }}{\text{=0.27}}_3{\text{±0.21}}_2{\mathrm{,f}}_{\mathrm{r\theta }}^{\prime }{\text{=0.07}}_1{\text{±0.28}}_0$ .