A fractional Brownian motion model for time series produced by constant temperature molecular dynamics simulations
Ημερομηνία
2002Λέξη-κλειδί
Επιτομή
In the present work we performed an analysis of time series of instantaneous temperature and pressure produced during constant temperature molecular dynamics. Simulations were applied to a nickel oxide grain boundary for a temperature range 0.15-0.80T(m), T-m being the melting point of the system. We performed a series of analysis for these time series including test for randomness, power spectrum, Hurst exponent and structure function test. Evidence of fractional Brownian motion was found. Pressure presents 1/f over the whole range of frequencies of the system while temperature presents a two-regime behavior: white noise at low frequencies and 1/f(alpha) at high frequencies with alpha increasing as a function of temperature. The origins of this behavior are discussed.