Development of a simultaneous measurement system of x-ray diffraction and raman spectra: Application to structural study of crystalline-phase transitions of chain molecules

2002 ◽  
Vol 40 (6) ◽  
pp. 495-506 ◽  
Author(s):  
Kohji Tashiro ◽  
Sobiroh Kariyo ◽  
Akihito Nishimori ◽  
Takashi Fujii ◽  
Seishi Saragai ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Raman Spectra ◽  
Structural Study ◽  
Measurement System ◽  
Crystalline Phase ◽  
Simultaneous Measurement ◽  
X Ray Diffraction ◽  
Chain Molecules ◽  
X Ray

Pressure-induced phase transitions in L-alanine, revisited

2010 ◽  
Vol 66 (4) ◽  
pp. 458-471 ◽  
Author(s):  
N. A. Tumanov ◽  
E. V. Boldyreva ◽  
B. A. Kolesov ◽  
A. V. Kurnosov ◽  
R. Quesada Cabrera
Keyword(s):  
Phase Transitions ◽  
Raman Spectra ◽  
Pressure Range ◽  
Monoclinic Phase ◽  
Structural Phase ◽  
Group Symmetry ◽  
Structural Phase Transitions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters

The effect of pressure on L-alanine has been studied by X-ray powder diffraction (up to 12.3 GPa), single-crystal X-ray diffraction, Raman spectroscopy and optical microscopy (up to ∼ 6 GPa). No structural phase transitions have been observed. At ∼ 2 GPa the cell parameters a and b become accidentally equal to each other, but without a change in space-group symmetry. Neither of two transitions reported by others (to a tetragonal phase at ∼ 2 GPa and to a monoclinic phase at ∼ 9 GPa) was observed. The changes in cell parameters were continuous up to the highest measured pressures and the cells remained orthorhombic. Some important changes in the intermolecular interactions occur, which also manifest themselves in the Raman spectra. Two new orthorhombic phases could be crystallized from a MeOH/EtOH/H2O pressure-transmitting mixture in the pressure range 0.8–4.7 GPa, but only if the sample was kept at these pressures for at least 1–2 d. The new phases converted back to L-alanine on decompression. Judging from the Raman spectra and cell parameters, the new phases are most probably not L-alanine but its solvates.

Direct observation of amorphous to crystalline phase transitions in Ge–Sb–Te thin films by grazing incidence X-ray diffraction method

2020 ◽  
Vol 31 (13) ◽  
pp. 10196-10206
Author(s):  
Sergey A. Kozyukhin ◽  
Ilja I. Nikolaev ◽  
Petr I. Lazarenko ◽  
Gleb A. Valkovskiy ◽  
Oleg Konovalov ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Transitions ◽  
Direct Observation ◽  
Crystalline Phase ◽  
Diffraction Method ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Provenance and Sedimentary Context of Clay Mineralogy in an Evolving Forearc Basin, Upper Cretaceous-Paleogene and Eocene Mudstones, San Joaquin Valley, California

Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 71
Author(s):  
Andrew Hurst ◽  
Michael Wilson ◽  
Antonio Grippa ◽  
Lyudmyla Wilson ◽  
Giuseppe Palladino ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Upper Cretaceous ◽  
Clay Fraction ◽  
Clay Mineralogy ◽  
Bulk Rock ◽  
X Ray Diffraction ◽  
Arc Volcanism ◽  
X Ray ◽  
Magmatic Arc ◽  
Tropical Weathering

Mudstone samples from the Moreno (Upper Cretaceous-Paleocene) and Kreyenhagen (Eocene) formations are analysed using X-ray diffraction (XRD) and X-ray fluorescence (XRF) to determine their mineralogy. Smectite (Reichweite R0) is the predominant phyllosilicate present, 48% to 71.7% bulk rock mineralogy (excluding carbonate cemented and highly bio siliceous samples) and 70% to 98% of the <2 μm clay fraction. Opal CT and less so cristobalite concentrations cause the main deviations from smectite dominance. Opal A is common only in the Upper Kreyenhagen. In the <2 μm fraction, the Moreno Fm is significantly more smectite-rich than the Kreyenhagen Fm. Smectite in the Moreno Fm was derived from the alteration of volcaniclastic debris from contemporaneous rhyolitic-dacitic magmatic arc volcanism. No tuff is preserved. Smectite in the Kreyenhagen Fm was derived from intense sub-tropical weathering of granitoid-dioritic terrane during the hypothermal period in the early to mid-Eocene; the derivation from local volcanism is unlikely. All samples had chemical indices of alteration (CIA) indicative of intense weathering of source terrane. Ferriferous enrichment and the occurrence of locally common kaolinite are contributory evidence for the intensity of weathering. Low concentration (max. 7.5%) of clinoptilolite in the Lower Kreyenhagen is possibly indicative of more open marine conditions than in the Upper Kreyenhagen. There is no evidence of volumetrically significant silicate diagenesis. The main diagenetic mineralisation is restricted to low-temperature silica phase transitions.

Temperature-induced structural phase transitions in RERhSn (RE = Y, Gd-Tm, Lu)

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Simon Engelbert ◽  
Rolf-Dieter Hoffmann ◽  
Jutta Kösters ◽  
Steffen Klenner ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Phase Transitions ◽  
Driving Force ◽  
Room Temperature ◽  
Structural Phase ◽  
Structural Phase Transitions ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray

Abstract The structures of the equiatomic stannides RERhSn with the smaller rare earth elements Y, Gd-Tm and Lu were reinvestigated on the basis of temperature-dependent single crystal X-ray diffraction data. GdRhSn crystallizes with the aristotype ZrNiAl at 293 and 90 K. For RE = Y, Tb, Ho and Er the HP-CeRuSn type (approximant with space group R3m) is already formed at room temperature, while DyRhSn adopts the HP-CeRuSn type below 280 K. TmRhSn and LuRhSn show incommensurate modulated variants with superspace groups P31m(1/3; 1/3; γ) 000 (No. 157.1.23.1) (γ = 3/8 for TmRhSn and γ = 2/5 for LuRhSn). The driving force for superstructure formation (modulation) is a strengthening of Rh–Sn bonding. The modulation is expressed in a 119Sn Mössbauer spectrum of DyRhSn at 78 K through line broadening.

X-ray diffraction study of phase transitions in iron(II) trisnioximate hexadecylboronate clathrochelate complex

2001 ◽  
Vol 46 (5) ◽  
pp. 758-770 ◽  
Author(s):  
I. I. Vorontsov ◽  
K. A. Potekhin ◽  
M. Yu. Antipin ◽  
Ya. Z. Voloshin ◽  
A. I. Stash ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Diffraction Study ◽  
X Ray Diffraction ◽  
X Ray
Sign in / Sign up

Export Citation Format

Share Document