Picosecond calorimetry: Time-resolved x-ray diffraction studies of liquid CH2Cl2

QC 20120228
Liquid phase time-resolved x-ray diffraction with 100 ps resolution has recently emerged as a powerful technique for probing the structural dynamics of transient photochemical species in solution. It is intrinsic to the method, however, that a structural signal is observed not only from the photochemical of interest but also from the embedding solvent matrix. To experimentally characterize the x-ray diffraction signal deriving from the solvent alone we performed time-resolved diffraction studies of a pure liquid sample over a time domain from -250 ps to 2.5 mu s. Multiphoton excitation was used to rapidly heat liquid CH2Cl2 using UV pulses of 100 fs duration. A significant x-ray diffraction signal is visible prior to the onset of thermal expansion, which characterizes a highly compressed superheated liquid. Liquid CH2Cl2 then expands as a shock wave propagates through the sample and the temporal dependence of this phenomenon is in good agreement with theory. An unexpectedly slow initial release of energy into the liquid as heat is observed from multiphoton excited CH2Cl2, revealing the presence of a metastable state of multiphoton excited CH2Cl2.

Vincent, JonathanUppsala universitet,Institutionen för fotokemi och molekylärvetenskap,Kemisk fysik(Swepub:uu)jovin173 (author)
Andersson, M.Chalmers tekniska högskola,Chalmers University of Technology (author)
Wöhri, Annemarie,1976Chalmers tekniska högskola,Chalmers University of Technology(Swepub:cth)wohri (author)
Gourdon, Pontus Emanuel,1978Chalmers tekniska högskola,Chalmers University of Technology(Swepub:cth)kb97gopo (author)
Poulsen, Jens Aage,1972Gothenburg University,Göteborgs universitet,Institutionen för kemi,Department of Chemistry,University of Gothenburg(Swepub:gu)xpouje (author)
Davidsson, JanUppsala universitet,Institutionen för fotokemi och molekylärvetenskap,Kemisk fysik(Swepub:uu)jandavid (author)
Neutze, Richard,1969Chalmers tekniska högskola,Chalmers University of Technology(Swepub:cth)xneuri (author)
Uppsala universitetInstitutionen för fotokemi och molekylärvetenskap (creator_code:org_t)

In:Journal of Chemical Physics: AIP Publishing124:23, s. 234507-0021-96061089-7690

By the author/editor: Georgiou, P.; Vincent, Jonatha ...; Andersson, M.; Wöhri, Annemarie ...; Gourdon, Pontus ...; Poulsen, Jens Aa ...; show more...; Davidsson, Jan; Neutze, Richard, ...; show less...

About the subject

By the university: Royal Institute of Technology; University of Gothenburg; Chalmers University of Technology; Uppsala University

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