INFRARED-SPECTRA OF SOME ISOTOPOMERS OF METHYLAMINE AND THE METHYLAMMONIUM ION - A THEORETICAL-STUDY

The normal mode frequencies of some isotopomers of methylamine and the methylammonium ion are examined theoretically using the GAUSSIAN 94 s et of quantum chemistry codes. In particular, deuteration of the NH2 a nd NH3+ hydrogen atoms, as well as the deuteration of the CH3 hydrogen atoms, and total deuteration of both methylamine and the methylammoni um ion are examined. Calculations are performed at the Hartree-Fock (H F) and second-order Moller-Plesset (MP2) levels of theory using a 6-31 1G* basis set. Correction factors for predominant vibrational motions at each level of theory are reported and compared for the eight molec ular species that are considered. (C) 1998 Elsevier Science B.V.