ACCURATE FORCE-CONSTANTS OF TRANS-1,3-BUTADIENE - A DIRECT APPROACH

Force constants of trans-1,3-butadiene have been obtained at the HF/DZP level and using the recently proposed RECOVES procedure. The RECOVES-HF/DZP force constant set, by definition, reproduces exactly the experimental frequencies for the parent molecule, and the vibrational frequencies predicted for different deuterated isotopomers are highly satisfactory. It has been found that the RECOVES procedure, in contrast to other scaling methods, appropriately compensates for the absence of electron correlation in the ab initio calculation. Presently derived force constants are discussed and compared with those of earlier investigators.