An algorithm for the uniform sampling of iso-energy surfaces and for the calculation of microcanonical averages.
In this article an algorithm is proposed to efficiently perform the uniform sampling of an iso-energy surface corresponding to a fixed potential energy U of a molecular system, and for calculating averages of certain quantities over microstates having this energy (microcanonical averages). The developed sampling technique is based upon the combination of a recently proposed method for performing constant potential energy molecular dynamics simulations [Rapallo, A. J Chem Phys 2004, 121, 4033] with well-established thermostatting techniques used in the framework of standard molecular dynamics simulations, such as the Andersen thermostat, and the Nose-Hoover chain thermostat. The proposed strategy leads to very accurate and drift-free potential energy conservation during the whole sampling process, and, very important, specially when dealing with high-dimensional or complicated potential functions, it does not require the calculation of the potential energy function hessian. The technique proved to be very reliable for sampling both low- and high-dimensional surfaces.
Rapallo
Arnaldo
A
ISMAC-Istituto per lo Studio delle Macromolecole del CNR, Via E. Bassini 15, 20133 Milano, Italy. a.rapallo@ismac.cnr.it
D000465:Algorithms; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003198:Computer Simulation; D006838:Hydrocarbons / Q000737:chemistry; D008958:Models, Molecular; D013499:Surface Properties
D006838:Hydrocarbons