Influence of thermostats on the calculations of heat capacities from Born-Oppenheimer molecular dynamics simulations

The temperature dependency of the vibrational molecular heat capacity of the copper dimer is calculated from classical Born‐Oppenheimer molecular dynamics (BOMD) simulations employing four different thermostats. The resulting heat capacity curves are compared with their the polyatomic ideal gas counterparts. It is shown that the Nosé‐Hoover chain thermostat yields realistic temperature profiles and reliable heat capacities. This result is also supported by the corresponding canonical phase space distribution. This work demonstrates that canonical BOMD simulations with the Nosé‐Hoover chain thermostat are well suited to obtain reliable thermodynamic properties for small finite systems. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010