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dc.contributor.authorLindgren, Johan
dc.contributor.authorKiljunen, Toni
dc.date.accessioned2014-01-21T11:40:06Z
dc.date.available2014-01-21T11:40:06Z
dc.date.issued2013
dc.identifier.citationLindgren, J., & Kiljunen, T. (2013). Excitation of rotons in parahydrogen crystals: The laser-induced-molecular-alignment mechanism. <i>Physical Review A</i>, <i>88</i>(4), 043420(15). <a href="https://doi.org/10.1103/PhysRevA.88.043420" target="_blank">https://doi.org/10.1103/PhysRevA.88.043420</a>
dc.identifier.otherCONVID_22992212
dc.identifier.otherTUTKAID_59069
dc.identifier.urihttps://jyx.jyu.fi/handle/123456789/42842
dc.description.abstractSolid parahydrogen (p-H₂) is known to support long-lived coherences, of the order of 100 ps, which enables high-resolution spectroscopy in the time domain. Rotational Raman-type excitations to sublevels of J=2 are delocalized due to electric-quadrupole–quadrupole coupling in p-H₂ crystals, and the resulting states can be characterized as rotons. Wave packets of rotons exhibit molecular alignment with respect to laboratory coordinates. Here the concept of field-free molecular alignment, induced by strong ultrashort laser pulses, is extended into a molecular solid case. We derive a solid-state analog for the gas-phase alignment measure and illustrate the time-dependent alignment degree in p-H₂crystals by numerical simulations. To underscore the Raman gain effect of the solid, general properties of the field-free alignment are revisited by comparing gaseous p-H₂ with N₂. The interplay between the polarization direction of the excitation pulses and the axis directionality of the crystal is shown to affect the alignment dynamics via the spatial (M=0,±1,±2 ) composition of the roton wave packets. We simulate experimental traces by incorporating the induced alignment degree in the calculation of heterodyne-detected realization of femtosecond pump-probe optical Kerr effect spectroscopy. With the help of dispersed, two-dimensional resolved images of the calculated signal we reproduce the experiment as a whole. To that end, the effects of probe chirp, shape, and power must be explored in detail. We find good agreement with previous experiments and unravel the ambiguity of tracing back the wave-packet composition from the signal; in particular, we find that the effect of quantum phase factors of all the components should be taken into account when explaining the signal properties.fi
dc.language.isoeng
dc.publisherAmerican Physical Society
dc.relation.ispartofseriesPhysical Review A
dc.relation.urihttp://pra.aps.org/browse
dc.subject.othermolecular alignment
dc.subject.otheroptical control
dc.titleExcitation of rotons in parahydrogen crystals: The laser-induced-molecular-alignment mechanism
dc.typearticle
dc.identifier.urnURN:NBN:fi:jyu-201401141052
dc.contributor.laitosKemian laitosfi
dc.contributor.laitosDepartment of Chemistryen
dc.contributor.oppiaineFysikaalinen kemiafi
dc.contributor.oppiaineNanoscience Centerfi
dc.contributor.oppiainePhysical Chemistryen
dc.contributor.oppiaineNanoscience Centeren
dc.type.urihttp://purl.org/eprint/type/JournalArticle
dc.date.updated2014-01-14T04:30:17Z
dc.type.coarjournal article
dc.description.reviewstatuspeerReviewed
dc.format.pagerange043420(15)
dc.relation.issn1050-2947
dc.relation.numberinseries4
dc.relation.volume88
dc.type.versionacceptedVersion
dc.rights.copyright© 2013 American Physical Society
dc.rights.accesslevelopenAccessfi
dc.relation.doi10.1103/PhysRevA.88.043420


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