Finite-size effects in molecular dynamics simulations: Static structure factor and compressibility. I. Theoretical method

Pair correlation function integrals: Computation and use

“…In addition, finite-size effects may affect the correlation functions in the accessible range. 31 Size-effects in the total correlation functions (not shown) are very subtle for dense systems with low compressibility. They can result in significant numerical inaccuracies in the reduced bulk modulus and c(r).…”

“…A method due to Verlet 42 aims to correct the correlation functions obtained from simulation for the effects of finite-sized systems, such as those summarized by Salacuse, Denton, and Egelstaff, 31 and to extend the correlation functions to longer ranges. The method was originally used for a pure Lennard-Jones fluid, with focus on the qualitative behavior of the direct correlation function and the structure factor, and later extended to a Lennard-Jones mixture.…”

“…30 The role of finite-size effects on the accuracy of the functions as the sampling limit is approached has also been discussed. 31 Several approaches have been proposed in order to correct the sampled distribution functions and extend them to long range, so that the integrals can be evaluated accurately. Weerasinghe and Smith 5 evaluated the integrals numerically using an appropriately selected truncation radius.…”

On the accurate direct computation of the isothermal compressibility for normal quantum simple fluids: Application to quantum hard spheres

“…One is the explicit effect that is associated with the fixing of S N N = particles in the simulation, and the other is the implicit effect that is related to the influence of the periodic boundary conditions. 44 Far from the critical point and for a sufficiently large sample size , S N the main influence on the simulation results is caused by the explicit effect, which becomes even more determining in the case of short-range interactions.…”

“…The results so obtained were based on (N, V, T) simulations and showed excellent agreement with experiments and other theoretical approaches. [27][28][29][32][33][34][35][36][37][38][39][40][41][42] Clearly, there are other general methods to obtain isothermal compressibilities for quantum fluids, such as the evaluation of the fluctuations in the (µ, V, T)-number of particles 43,44 or in the (N, P, T)-volume. 43,15(b)- (c), 45 To carry out extensive grand ensemble simulations appears to be a daunting task in the quantum case.…”