Inelastic neutron scattering (INS) studies on low frequency vibrations of 1,4-benzoquinone

Inelastic neutron scattering (INS) infrared (IR) and Raman (R) spectra in t he region below 1700 cm(-1) of solid 1,4-benzoquinone (p-BQ) are compared w ith calculated frequencies and intensities for the gas phase. In the case o f INS spectra a very good agreement is found when the frequency scaling fac tor markedly higher than unity (1.05) is assumed. This is most probably due to the fact that in the solid state all hydrogen and oxygen atoms are invo lved in the C-H . . .O hydrogen bond formation. The internal dynamics of p- BQ molecules reflected in the low frequency region is to a marked extent af fected by these interactions. The environment effect is best reflected in t he INS spectra recorded at 22 K. The. complementarity of INS, IR and R spec tra, appearance of overtones and summation modes and overlapping of closely located bands are discussed. (C) 2001 Elsevier Science B.V. All rights res erved.