eprintid: 1458328 rev_number: 30 eprint_status: archive userid: 608 dir: disk0/01/45/83/28 datestamp: 2014-12-13 20:52:34 lastmod: 2021-10-24 23:35:50 status_changed: 2016-02-22 09:50:00 type: article metadata_visibility: show item_issues_count: 0 creators_name: Stinson, JL creators_name: Kathmann, SM creators_name: Ford, IJ title: Dynamical consequences of a constraint on the Langevin thermostat in molecular cluster simulation ispublished: pub divisions: UCL divisions: B04 divisions: C06 divisions: F60 keywords: Langevin thermostat, small system, constraints note: This is an Accepted Manuscript of an article published by Taylor & Francis in Molecular Physics on 19/05/14, available online: http://www.tandfonline.com/10.1080/00268976.2014.917732. abstract: © 2014 Taylor and Francis. We investigate some unusual behaviour observed while performing molecular dynamics simulations of small molecular clusters using a constrained Langevin thermostat. Atoms appear to be thermalised to different temperatures that depend on their mass and on the total number of particles in the system. The deviation from the zeroth law of thermodynamics can be considerable for small systems of heavy and light particles. We trace this behaviour to the absence of thermal noise acting on the centre of mass of the system. This is demonstrated by solving the stochastic dynamics for the constrained thermostat and comparing the results with simulation data. By removing the constraint, the Langevin thermostat may be restored to its intended behaviour. We also investigate a Langevin thermostat constrained to have zero total force acting on its centre of mass, and find similar deficiencies. date: 2014-01-01 official_url: http://dx.doi.org/10.1080/00268976.2014.917732 vfaculties: VMPS oa_status: green full_text_type: other language: eng primo: open primo_central: open_green article_type_text: Journal Article verified: verified_manual elements_source: Scopus elements_id: 999133 doi: 10.1080/00268976.2014.917732 lyricists_name: Ford, Ian lyricists_id: IJFOR04 full_text_status: public publication: Molecular Physics volume: 112 number: 22 pagerange: 2920-2923 issn: 1362-3028 citation: Stinson, JL; Kathmann, SM; Ford, IJ; (2014) Dynamical consequences of a constraint on the Langevin thermostat in molecular cluster simulation. Molecular Physics , 112 (22) pp. 2920-2923. 10.1080/00268976.2014.917732 <https://doi.org/10.1080/00268976.2014.917732>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/1458328/1/LangevinThermostat_Paper_ReDraft1_IJFclean.pdf