Knowledge Bank

“Using the potential energy constants obtained in previous investigations in this laboratory, the mean square amplitudes of vibration were obtained for $CF4,CCI4$, and $CBr4$ at $298.16\circ K$ by Cyvin’s secular equation $method.1$ The electron diffraction data (available only for $CCI4$ at $295^{\circ} K $)compareveryfavorablywithpresentcalculatedvalues.Therotationaldistortionconstantshavealsobeencalculatedforthesemoleculesfromthepotentialenergyconstants,andtheshrinkageeffectsintheinternucleardistanceshavebeendetermined.Themeansquareamplitudesin\backslash AA$^{2}$ for $CF4,CCI4$, and $CBr4$ are respectively: 0.001876, 0.002484, and 0.002643 for $\sigma r(C-X)$, where $X=F, $CL, or Br; and 0.002936, 0.004636, and 0.005877 for $\sigma d(X\dots X)$. The $DJ$ values for $CF4,CCI4$, and $CBr4$ are respectively 1650, 176.7, and 26.5 c/s. The corresponding $DJr$ values are 1156, 132.9, and 21.1 c/s.”