TY - JOUR

T1 - Addressing Dynamics at Catalytic Heterogeneous Interfaces with DFT-MD

T2 - Anomalous Temperature Distributions from Commonly Used Thermostats

AU - Korpelin, Ville

AU - Kiljunen, Toni

AU - Melander, Marko M.

AU - Caro, Miguel A.

AU - Kristoffersen, Henrik H.

AU - Mammen, Nisha

AU - Apaja, Vesa

AU - Honkala, Karoliina

N1 - Funding Information: The project was funded by the Academy of Finland projects 307853 (M.M.M.), 338228 (M.M.M.), 310574 (M.A.C.), 330488 (M.A.C.), 317739 (M.M.M., N.M., and K.H.), and 332290 (N.M.). M.M.M. and K.H. also acknowledge Jane and Aatos Erkko Foundation for funding to the LACOR project. The computational resources were provided by CSC-IT Center for Science Ltd through the pilot project initiatives (H2OINTE and FLUXMD). We also thank Professor Jakob Schiøtz for helpful discussions related to the thermostats implemented in ASE. Prof. Gerrit Groenhof and Dr. Dimitry Morozov are acknowledged for careful reading of the work and their fruitful comments. Publisher Copyright: © 2022 The Authors. Published by American Chemical Society.

PY - 2022/3/24

Y1 - 2022/3/24

N2 - Density functional theory-based molecular dynamics (DFT-MD) has been widely used for studying the chemistry of heterogeneous interfacial systems under operational conditions. We report frequently overlooked errors in thermostated or constant-temperature DFT-MD simulations applied to study (electro)catalytic chemistry. Our results demonstrate that commonly used thermostats such as Nosé-Hoover, Berendsen, and simple velocity-rescaling methods fail to provide a reliable temperature description for systems considered. Instead, nonconstant temperatures and large temperature gradients within the different parts of the system are observed. The errors are not a "feature"of any particular code but are present in several ab initio molecular dynamics implementations. This uneven temperature distribution, due to inadequate thermostatting, is well-known in the classical MD community, where it is ascribed to the failure in kinetic energy equipartition among different degrees of freedom in heterogeneous systems (Harvey et al. J. Comput. Chem. 1998, 726-740) and termed the flying ice cube effect. We provide tantamount evidence that interfacial systems are susceptible to substantial flying ice cube effects and demonstrate that the traditional Nosé-Hoover and Berendsen thermostats should be applied with care when simulating, for example, catalytic properties or structures of solvated interfaces and supported clusters. We conclude that the flying ice cube effect in these systems can be conveniently avoided using Langevin dynamics.

AB - Density functional theory-based molecular dynamics (DFT-MD) has been widely used for studying the chemistry of heterogeneous interfacial systems under operational conditions. We report frequently overlooked errors in thermostated or constant-temperature DFT-MD simulations applied to study (electro)catalytic chemistry. Our results demonstrate that commonly used thermostats such as Nosé-Hoover, Berendsen, and simple velocity-rescaling methods fail to provide a reliable temperature description for systems considered. Instead, nonconstant temperatures and large temperature gradients within the different parts of the system are observed. The errors are not a "feature"of any particular code but are present in several ab initio molecular dynamics implementations. This uneven temperature distribution, due to inadequate thermostatting, is well-known in the classical MD community, where it is ascribed to the failure in kinetic energy equipartition among different degrees of freedom in heterogeneous systems (Harvey et al. J. Comput. Chem. 1998, 726-740) and termed the flying ice cube effect. We provide tantamount evidence that interfacial systems are susceptible to substantial flying ice cube effects and demonstrate that the traditional Nosé-Hoover and Berendsen thermostats should be applied with care when simulating, for example, catalytic properties or structures of solvated interfaces and supported clusters. We conclude that the flying ice cube effect in these systems can be conveniently avoided using Langevin dynamics.

U2 - 10.1021/acs.jpclett.2c00230

DO - 10.1021/acs.jpclett.2c00230

M3 - Journal article

C2 - 35297635

AN - SCOPUS:85127929935

VL - 13

SP - 2644

EP - 2652

JO - Journal of Physical Chemistry Letters

JF - Journal of Physical Chemistry Letters

SN - 1948-7185

IS - 11

ER -