title: Applicability of Quantum Thermal Baths to Complex Many-Body Systems with Various Degrees of Anharmonicity.
abstract: The semiclassical method of quantum thermal baths by colored noise thermostats has been used to simulate various atomic systems in the molecular and bulk limits, at finite temperature and in moderately to strongly anharmonic regimes. In all cases, the method performs relatively well against alternative approaches in predicting correct energetic properties, including in the presence of phase changes, provided that vibrational delocalization is not too strong-neon appearing already as an upper limiting case. In contrast, the dynamical behavior inferred from global indicators such as the root-mean-square bond length fluctuation index or the vibrational spectrum reveals more marked differences caused by zero-point energy leakage, except in the case of isolated molecules with well separated vibrational modes. To correct for such deficiencies and reduce the undesired transfer among modes, empirical modifications of the noise power spectral density were attempted to better describe thermal equilibrium but still failed when used as semiclassical preparation for microcanonical trajectories.
authors.affiliation: Departamento de Física and IUdEA, Universidad de La Laguna , 38205, La Laguna, Tenerife, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Hernández-Rojas
authors.affiliation: Laboratoire Interdisciplinaire de Physique, Rue de la Piscine, Campus Saint Martin d'Hères, 38000 Grenoble, France.
authors.forename: Florent
authors.initials: F
authors.lastname: Calvo
authors.affiliation: Instituto Química-Física Rocasolano, Consejo Superior de Investigaciones Científicas , Calle Serrano 119, 28006 Madrid, Spain.
authors.forename: Eva Gonzalez
authors.initials: EG
authors.lastname: Noya