Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

Twisting of the NMe₂ group in p-N,N-dimethylaminobenzonitrile (DMABN) was investigated using AM1 semiempirical method with configuration interaction. Effect of polar media was considered by placing + and - charge centers ("sparkles") at appropriate places opposite the molecule. Optimized ground state geometry of DMABN is slightly twisted with the lowest vertical excited state of ¹B character. As the polarity of media increases and/or the - NMe₂ group twists, the symmetric ¹A excited state having considerable charge separation becomes energetically favorable. Anomalous long-wavelength emission of DMABN comes from this state.