Influence of the quench rate and the pressure on the glass transition temperature in selenium

We report a molecular dynamics investigation of the glass transition temperature in selenium at pressures ranging from 0 to 6 GPa as a function of the quench rate, Qr . For moderate pressures the specific volume of the glass depends strongly on the quench rate, whereas the specific enthalpy varies only little. We find for both volume and energy a linear dependence on the quench-rate-dependent glass transition temperature. The slopes of these curves reflect the different energy scales of void formation, interand intrachain interactions. The extrapolated glass transition temperatures for quench rates of order K/s agree with the experimental ones within 20%. Applying a pressure of 1 GPa the glass transition temperature is raised by 37 K. For the same Qr , the transition temperature Tg is much higher for simulations using fixed volume conditions ~NVT ensemble! than for the ones using fixed pressure ~NPT ensemble! when one compares results for equal pressure at T50. © 2002 American Institute of Physics. @DOI: 10.1063/1.1492797#