Vibrational spectra and normal coordinate analysis of 4-(dimethylamino)benzaldehyde and selected isotopic derivatives.

Results of a normal coordinate analysis based on infrared and Raman spectra of six isotopic forms of 4-(dimethylamino)benzaldehyde are reported (DABA, DABA-CDO, DABA-13CDO, DABA-13CHO, DABA-CHO18O, and DABA-3,5-D). Cs point group symmetry has been applied and all motions except the internal rotations of the dimethylamino and the two methyl groups have been used to generate symmetry coordinates. The potential energy distributions have lead to revision and extension of previous assignments. The force field and the forms of the normal modes are in excellent agreement with those reported for similar molecules.