MONTE-CARLO SIMULATIONS OF THE INTERLAMELLAR SPACING IN MODEL N-ALKANE CRYSTALS

Monte Carlo simulations are carried out on a simple one-dimensional mo del of n-alkane crystals to investigate the chain length dependence of the interlamellar spacing, which has implications with regard to the Raman spectra of n-alkane crystals. The results of these simulations s how no significant chain length dependence for the interlamellar spaci ng. A quasiharmonic analysis reveals that the absence of a chain-lengt h dependence is due to a cancellation of the effects of the intrachain vibrations, which act to increase the interlamellar spacing for longe r chain lengths, by the effects of interchain vibrations, which act to decrease the interlamellar spacing for longer chain lengths. (C) 1998 American Institute of Physics.