Inelastic neutron scattering studies on dichloro-1,4-benzoquinones.

Inelastic neutron scattering (INS) spectra of 2,6-dichloro- and 2,5-dichloro-1,4-benzoquinone were compared with Raman and infra-red (IR) spectra and analysed in detail below 1800 cm(-1). The analysis was based on calculations tending towards simulation of spectra by using GAUSSIAN (HF, DFT/B3LYP and BLYP/6-31G(d,p)), and auntieCLIMAX programs. The correlations between calculated and experimental (either INS or Raman and IR) frequencies enabled to analyse the problem of scaling factors (SFs). The advantages of INS technique was shown in studies of low frequency vibrations with participation of H-atoms. The macroscopic lattice effect at low temperatures on INS spectra is discussed.