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dc.contributor.authorWillatt, Michael Jen
dc.contributor.authorCeriotti, Micheleen
dc.contributor.authorAlthorpe, Stuarten
dc.date.accessioned2018-02-22T14:39:30Z
dc.date.available2018-02-22T14:39:30Z
dc.date.issued2018-03en
dc.identifier.issn0021-9606
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/273453
dc.description.abstractMatsubara dynamics is the quantum-Boltzmann-conserving classical dynamics which remains when real-time coherences are taken out of the exact quantum Liouvillian [J. Chem. Phys. 142, 134103 (2015)]; because of a phase-term, it cannot be used as a practical method without further approximation. Recently, Smith et al. [J. Chem. Phys. 142, 244112 (2015)] developed a ‘planetary’ model dynamics which conserves the Feynman-Kleinert (FK) approximation to the quantum Boltzmann distribution. Here, we show that, for moderately anharmonic potentials, the planetary dynamics gives a good approximation to Matsubara trajectories on the FK potential surface, by decoupling the centroid trajectory from the locally harmonic Matsubara fluctuations, which reduce to a single phase-less fluctuation particle (the ‘planet’). We also show that the FK effective frequency can be approximated by a direct integral over these fluctuations, obviating the need to solve iterative equations. This modification, together with use of thermostatted ring-polymer molecular dynamics (TRPMD), allows us to test the planetary model on water (gas-phase, liquid and ice), using the q-TIP4P/F potential surface. The ‘planetary’ fluctuations give a poor approximation to the rotational/librational bands in the infrared spectrum, but a good approxima- tion to the bend and stretch bands, where the fluctuation lineshape is found to be motionally narrowed by the vibrations of the centroid.
dc.format.mediumPrinten
dc.languageengen
dc.titleApproximating Matsubara dynamics using the planetary model: Tests on liquid water and ice.en
dc.typeArticle
prism.issueIdentifier10en
prism.publicationDate2018en
prism.publicationNameThe Journal of chemical physicsen
prism.startingPage102336
prism.volume148en
dc.identifier.doi10.17863/CAM.20488
dcterms.dateAccepted2017-12-08en
rioxxterms.versionofrecord10.1063/1.5004808en
rioxxterms.versionAM*
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2018-03en
dc.contributor.orcidWillatt, Michael J [0000-0002-2916-1233]
dc.contributor.orcidCeriotti, Michele [0000-0003-2571-2832]
dc.contributor.orcidAlthorpe, Stuart [0000-0003-1288-8070]
dc.identifier.eissn1089-7690
rioxxterms.typeJournal Article/Reviewen
rioxxterms.freetoread.startdate2019-01-12


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