Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/21806
Share/Export:
logo share SHARE logo core CORE BASE
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL | DATACITE
Title

Anharmonic effects on the structural and vibrational properties of the ethyl radical: A path integral Monte Carlo study

AuthorsLópez Ciudad, Telesforo; Ramírez, Rafael CSIC ORCID; Schulte, J.; Böhm, Michael C.
Issue Date22-Aug-2003
PublisherAmerican Institute of Physics
CitationJournal of Chemical Physics 119(8): 4328 (2003)
AbstractThe structural and vibrational properties of the ethyl radical have been investigated by a series of finite temperature simulations that treat the nuclei as quantum particles. The potential energy surface of the electronic ground state has been described by a nonorthogonal tight-binding Hamiltonian that provides results in reasonable agreement with ab initio methods. The quantum nature of the nuclei has been described by path integral Monte Carlo simulations at temperatures between 25 and 1000 K. Special interest deserves the determination of anharmonic and tunneling effects in the zero-point vibrational structure. In particular, we have studied the influence of anharmonic effects both on the mean value and the quantum fluctuations of equilibrium bond lengths and bond angles. The local structure of the radical center is found to be planar as a result of the zero-point motion of the atomic nuclei, even though the minimum energy configuration exhibits a pyramidal structure for this center. Anharmonic effects in the fundamental vibrational modes of the molecule are studied by a nonperturbative approach based on the centroid density. This function is a path integral concept that provides information on the static response of the system to applied external forces. Our study reveals a softening of the stretching modes associated with the C–H bonds and a hardening of the out-of-plane rocking motion of the methylene group. Both effects are in good agreement with experimental and ab initio data. The softening of the C–C stretching mode predicted by our simulations suggests a revision of the currently accepted experimental assignment for two fundamental vibrations of the ethyl radical. The tunneling of an H atom between the methyl and methylene groups has been investigated. These simulations should contribute to the open question whether or not this process is responsible for the changes in the electron spin resonance spectrum at low temperatures.
Description11 pages, 11 figures, 6 tables.
Publisher version (URL)http://dx.doi.org/10.1063/1.1591731
URIhttp://hdl.handle.net/10261/21806
DOI10.1063/1.1591731
ISSN0021-9606
Appears in Collections:(ICMM) Artículos




Files in This Item:
File Description SizeFormat
Anharmonic effects.pdf297,26 kBAdobe PDFThumbnail
View/Open
Show full item record
Review this work

SCOPUSTM   
Citations

24
checked on May 21, 2022

WEB OF SCIENCETM
Citations

22
checked on May 22, 2022

Page view(s)

319
checked on May 25, 2022

Download(s)

233
checked on May 25, 2022

Google ScholarTM

Check

Altmetric

Dimensions


WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.