000030570 001__ 30570
000030570 005__ 20150420164423.0
000030570 0248_ $$aoai:doc.rero.ch:20121109093350-NI$$punifr$$ppostprint$$prero_explore$$particle$$zthesis_urn$$zreport$$zthesis$$zbook$$zjournal$$zcdu549$$zcdu16$$zpreprint$$zcdu1$$zdissertation$$zcdu34
000030570 041__ $$aeng
000030570 080__ $$a549
000030570 100__ $$aTrittschack, Roy$$uDepartment of Geosciences, University of Fribourg, Switzerland
000030570 245__ $$9eng$$aIn situ high-temperature Raman and FTIR spectroscopy of the phase transformation of lizardite
000030570 269__ $$c2012
000030570 520__ $$9eng$$aA temperature-dependent in situ micro-FTIR and micro-Raman spectroscopic investigation was performed on powdered (FTIR, Raman) and single-crystal (Raman) lizardite-1<em>T</em> samples between room temperature and 819 °C. Between room temperature and 665 °C, the OH stretching bands shift to lower wavenumbers, demonstrating a weak expansion of the O3-H3…O2 interlayer distance. Band deconvolution of FTIR and Raman spectra at room temperature show differences in the number of bands in the OH stretching region with respect to group theory: four (FTIR) and six (Raman) OH stretching bands, respectively. This number reduces to four (Raman) at non-ambient temperatures either caused by LO-TO splitting, the presence of non-structural OH species or the presence of different lizardite polytypes and/or serpentine polymorphs as well as defects. During dehydroxylation, the evolution of the integrated intensity of the OH bands suggests a transport of hydrogen and oxygen as individual ions/molecule or OH⁻. A significant change in Raman spectra occurs between 639 and 665 °C with most lizardite peaks disappearing contemporaneously with the appearance of forsterite-related features and new, non-forsterite bands at 183, 350, and 670 cm⁻¹. A further band appears at 1000 cm⁻¹ at 690 °C. The long stability of Si-O-related bands indicates a delayed decomposition of the tetrahedral sheet with respect to the dehydroxylation of the octahedral sheet. Moreover, evidence for a small change in the ditrigonal distortion angle during heating is given. In general, all appearing non-forsterite-related frequencies are similar to Raman data of talc and this indicates the presence of a talc-like intermediate.
000030570 695__ $$9eng$$aLizardite ; dehydroxylation ; Raman ; and FTIR spectroscopy ; talc-like intermediate
000030570 700__ $$aGrobéty, Bernard$$uDepartment of Geosciences, University of Fribourg, Switzerland
000030570 700__ $$aKoch-Müller, Monika$$uGeoForschungsZentrum Potsdam, Germany
000030570 773__ $$g2012/97/11-12/1965-1976$$tAmerican Mineralogist
000030570 775__ $$gPublished version$$ohttp://dx.doi.org/10.2138/am.2012.4162
000030570 8564_ $$fgro_ish.pdf$$qapplication/pdf$$s1256848$$uhttp://doc.rero.ch/record/30570/files/gro_ish.pdf$$yorder:1$$zpdf
000030570 918__ $$aFaculté des sciences$$bDécanat, Ch. du Musée 6A, 1700 Fribourg$$cGéosciences
000030570 919__ $$aUniversité de Fribourg$$bFribourg$$ddoc.support@rero.ch
000030570 980__ $$aPOSTPRINT$$bUNIFR$$fART_JOURNAL
000030570 990__ $$a20121109093350-NI