Modelling the influence of nonbonded interactions on the electronic structure of dimethylaminobentonitrile

In the framework of studying the nature of the low-temperature phase transition in p-(N,N'-dimethylamino)benzonitrile (DMABN) crystals, the influence of intermolecular interactions on the electronic structure of the molecule was modelled by quantum-chemical calculations using the SCF MO method on the 3-21G/6-31G* basis. It was shown that a small variation in the mutual orientation of the molecules at a phase transition leads to transformations in their electronic structure. which can be interpreted as a change in the thermodynamic parameters of the DMABN molecules in the crystal. These data suggest that the changes of electronic structure of molecules in the crystal caused the low-temperature phase transition in the DMABN crystals. (C) 1998 Elsevier Science Ltd. All rights reserved.