Millimeter Wave Spectra and Centrifugal Stretching Constants of the Methyl Halides

摘要

HighJtransitions of the methyl halides have been measured and have been used to calculate accurate values for the centrifugal distortion constants.The values obtained forBO, DJJ,andDJKare (in Mc/sec and kc/sec, respectively); CH3middot;F19, 25 536.11, 59.3, 445; CH3middot;Cl35, 13 292.86, 18.1, 198; CH3middot;Br79, 9568.20, 9.9, 128.3; CH3middot;Br81, 9531.82, 9.7, 127.4; CH3middot;I127, 7501.30, 6.28, 98.5.The newDJJvalue for CH3middot;Cl35is in good agreement with the value of 18.4 kc/sec theoretically predicted by Chang and Dennison.For all four molecules theDJJconstants were found to be in good agreement with those predicted from Kratzer's formulaDJJequals;4BO3sol;ohgr;2,where ohgr; is the vibrational frequency corresponding to the stretching of the carbon halogen bond.