Conformational phase transition of deuterated p-bromobenzyl alcohol as studied by neutron powder diffraction

A neutron powder diffraction study on the crystal structure of the title compound (p-Br–C6D4–CD2–OD) confirmed that a first-order phase transition at Tt1=229 K accompanied a drastic change in the molecular conformation caused by a discontinuous rotational shift of the hydroxyl hydrogen atom around the C(D2)–O(D) bond. At T<Tt1, a contraction of the unit cell volume of ∼1% was found when compared to that of the normal compound (p-Br–C6H4–CH2–OH).

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Investigation of the Orbital and magnetic orderings in VF3

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s205327331408632x ◽

2014 ◽

Vol 70 (a1) ◽

pp. C1367-C1367

Author(s):

Gwilherm Nénert ◽

Patrick Reuvekamp ◽

Christina Drathen ◽

Roland Eger ◽

F Kraus ◽

...

Keyword(s):

Phase Transition ◽

Heat Capacity ◽

Structural Investigation ◽

Magnetic Moments ◽

Neutron Powder Diffraction ◽

Antiferromagnetic Order ◽

Magnetic Frustration ◽

First Order ◽

First Order Phase Transition ◽

First Order Phase

We report on a magnetic and structural investigation of layered antiferromagnetic system vanadium (III) fluoride. VF3 crystallizes in a distorted ReO3 structure (R-3c) with rotated undistorted VF6 octahedra. The V3+ cations are arranged in a triangular lattice with the possibility of exhibiting magnetic frustration. Polycrystalline samples of VF3 were investigated using heat capacity, dielectric, magnetic susceptibility, synchrotron and neutron powder diffraction methods. Combining our results, we report the first evidence for a first order phase transition resulting from the ordering of the t2g orbitals below 105-110 K. This transition reduces the symmetry to C2/c. We further confirm that VF3 undergoes a long-range antiferromagnetic order at ∼19 K in accordance with literature [1]. The antiferromagnetic order results in a magnetic structure with the magnetic moments alternating between a parallel and b parallel alignments in the ab plane.

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Surface ordering and destruction of the first order phase transition smectic A-smectic C* in free standing smectic films

Journal de Physique II ◽

10.1051/jp2:1994237 ◽

1994 ◽

Vol 4 (10) ◽

pp. 1865-1874 ◽

Cited By ~ 10

Author(s):

E. Demikhov ◽

U. Hoffmann ◽

H. Stegemeyer

Keyword(s):

Phase Transition ◽

Order Phase Transition ◽

Free Standing ◽

First Order ◽

Surface Ordering ◽

Smectic A ◽

Smectic C ◽

First Order Phase Transition ◽

First Order Phase

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Gravitational wave signals of dark matter freeze-out

Journal of High Energy Physics ◽

10.1007/jhep02(2021)022 ◽

2021 ◽

Vol 2021 (2) ◽

Cited By ~ 3

Author(s):

Danny Marfatia ◽

Po-Yan Tseng

Keyword(s):

Phase Transition ◽

Dark Matter ◽

Gravitational Waves ◽

Order Phase Transition ◽

First Order ◽

Stochastic Background ◽

First Order Phase Transition ◽

Relic Abundance ◽

First Order Phase ◽

Freeze Out

Abstract We study the stochastic background of gravitational waves which accompany the sudden freeze-out of dark matter triggered by a cosmological first order phase transition that endows dark matter with mass. We consider models that produce the measured dark matter relic abundance via (1) bubble filtering, and (2) inflation and reheating, and show that gravitational waves from these mechanisms are detectable at future interferometers.

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Dark Matter production from relativistic bubble walls

Journal of High Energy Physics ◽

10.1007/jhep03(2021)288 ◽

2021 ◽

Vol 2021 (3) ◽

Author(s):

Aleksandr Azatov ◽

Miguel Vanvlasselaer ◽

Wen Yin

Keyword(s):

Phase Transition ◽

Dark Matter ◽

Electroweak Phase Transition ◽

First Order ◽

Matter Production ◽

First Order Phase Transition ◽

Relic Abundance ◽

Higgs Portal ◽

First Order Phase ◽

Gravitational Background

Abstract In this paper we present a novel mechanism for producing the observed Dark Matter (DM) relic abundance during the First Order Phase Transition (FOPT) in the early universe. We show that the bubble expansion with ultra-relativistic velocities can lead to the abundance of DM particles with masses much larger than the scale of the transition. We study this non-thermal production mechanism in the context of a generic phase transition and the electroweak phase transition. The application of the mechanism to the Higgs portal DM as well as the signal in the Stochastic Gravitational Background are discussed.

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