scholarly journals Brillouin Light Scattering Study of Microscopic Structure and Dynamics in Pyrrolidinium Based Ionic Liquids

2020 ◽  
Author(s):  
Supti Das ◽  
Dhanya Radhakrishnan ◽  
Venkata. S. Bhadram ◽  
Chandrabhas Narayana ◽  
Aninda J. Bhattacharyya
Keyword(s):  
Ionic Liquids ◽  
Phase Transitions ◽  
Light Scattering ◽  
Solid Phase ◽  
Microscopic Structure ◽  
Temperature Dependent ◽  
Brillouin Light Scattering ◽  
Acoustic Modes ◽  
Structure And Dynamics ◽  
Acoustic Velocities

<p>Pyrrolidinium based ionic liquids are known to be good ionic conductors even in solid-state around room temperature, which is attributed to the highly disordered plastic crystalline phase. Moreover, these ionic liquids are characterized by multiple phase transitions which include plastic, structural glass, and glassy crystal phases with varying levels of molecular disorder. Temperature-dependent Brillouin light scattering is used to investigate the phase transitions in a series of alkylmethylpyrrolidinium Bis(trifluoromethanesulfonyl) imides (P<i><sub>1n</sub></i>TFSI, n=1,2,4). Brillouin spectral features such as the number of acoustic modes, their shape, and linewidth provide the picture of different disordered phases resultant of dynamics at the microscopic scale. The longitudinal and transverse acoustic velocities in different phases are determined from the corresponding acoustic mode frequencies (Brillouin shift). Extremely low acoustic velocities in the solid phase of P<i><sub>11</sub></i>TFSI and P<i><sub>12</sub></i>TFSI are a consequence of a high degree of disorder and plasticity present in the system. Anomalous temperature-dependent behavior of linewidth and asymmetric (Fano) line shape of acoustic modes observed in certain phases of P<i><sub>1n</sub></i>TFSI could be due to the strong coupling between the Brillouin central peak and the acoustic phonons. The present results establish that the Brillouin light scattering technique can be efficiently used to understand the complex phase behavior, microscopic structure, and dynamics of ionic liquids.</p>

scholarly journals Brillouin Light Scattering Study of Microscopic Structure and Dynamics in Pyrrolidinium Based Ionic Liquids

2020 ◽  
Author(s):  
Supti Das ◽  
Dhanya Radhakrishnan ◽  
Venkata. S. Bhadram ◽  
Chandrabhas Narayana ◽  
Aninda J. Bhattacharyya
Keyword(s):  
Ionic Liquids ◽  
Phase Transitions ◽  
Light Scattering ◽  
Solid Phase ◽  
Microscopic Structure ◽  
Temperature Dependent ◽  
Brillouin Light Scattering ◽  
Acoustic Modes ◽  
Structure And Dynamics ◽  
Acoustic Velocities

<p>Pyrrolidinium based ionic liquids are known to be good ionic conductors even in solid-state around room temperature, which is attributed to the highly disordered plastic crystalline phase. Moreover, these ionic liquids are characterized by multiple phase transitions which include plastic, structural glass, and glassy crystal phases with varying levels of molecular disorder. Temperature-dependent Brillouin light scattering is used to investigate the phase transitions in a series of alkylmethylpyrrolidinium Bis(trifluoromethanesulfonyl) imides (P<i><sub>1n</sub></i>TFSI, n=1,2,4). Brillouin spectral features such as the number of acoustic modes, their shape, and linewidth provide the picture of different disordered phases resultant of dynamics at the microscopic scale. The longitudinal and transverse acoustic velocities in different phases are determined from the corresponding acoustic mode frequencies (Brillouin shift). Extremely low acoustic velocities in the solid phase of P<i><sub>11</sub></i>TFSI and P<i><sub>12</sub></i>TFSI are a consequence of a high degree of disorder and plasticity present in the system. Anomalous temperature-dependent behavior of linewidth and asymmetric (Fano) line shape of acoustic modes observed in certain phases of P<i><sub>1n</sub></i>TFSI could be due to the strong coupling between the Brillouin central peak and the acoustic phonons. The present results establish that the Brillouin light scattering technique can be efficiently used to understand the complex phase behavior, microscopic structure, and dynamics of ionic liquids.</p>

Brillouin light scattering study of microscopic structure and dynamics in pyrrolidinium salt based ionic liquids

2021 ◽  
Vol 363 ◽  
pp. 115603
Author(s):  
Supti Das ◽  
Dhanya Radhakrishnan ◽  
Venkata S. Bhadram ◽  
Chandrabhas Narayana ◽  
Aninda J. Bhattacharyya
Keyword(s):  
Ionic Liquids ◽  
Light Scattering ◽  
Microscopic Structure ◽  
Brillouin Light Scattering ◽  
Structure And Dynamics ◽  
Scattering Study

Temperature-dependent spin-wave behavior in Co/CoO bilayers studied by Brillouin light scattering

2000 ◽  
Vol 62 (10) ◽  
pp. 6429-6436 ◽  
Author(s):  
A. Ercole ◽  
W. Lew ◽  
G. Lauhoff ◽  
E. Kernohan ◽  
J. Lee ◽  
...  
Keyword(s):  
Light Scattering ◽  
Spin Wave ◽  
Temperature Dependent ◽  
Brillouin Light Scattering

Sezawa and love modes in Co/Cu superlattices

Open Physics ◽  
2003 ◽  
Vol 1 (4) ◽  
Author(s):  
Tomasz Błachowicz
Keyword(s):  
Light Scattering ◽  
Boundary Conditions ◽  
Theoretical Approach ◽  
Theoretical Study ◽  
Experimental Results ◽  
Brillouin Light Scattering ◽  
Acoustic Modes ◽  
Scattering Measurements

AbstractIn this paper detailed theoretical study and experimental results concerning acoustic surface and undersurface propagation modes in multilayered Co/Cu superlattices are provided. The theoretical approach was adopted from that of Adler and Farnel. Experimental results were obtained in Brillouin light-scattering measurements. The Sezawa and Love acoustic modes were observed as a result of boundary conditions at the interface between hexagonal and cubic structures.

Untersuchungen zur Polymorphie der Cäsium-Dodekahalogeno-closo-Dodekaborate Cs2[B12X12] (X = Cl–I)

2020 ◽  
Vol 75 (8) ◽  
pp. 777-790
Author(s):  
Ioannis Tiritiris ◽  
Kevin U. Bareiß ◽  
Thomas Schleid
Keyword(s):  
Phase Transitions ◽  
Defect Structure ◽  
Room Temperature ◽  
Solid Phase ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Space Group ◽  
X Ray ◽  
Cubic System ◽  
Cesium Salts

AbstractThermoanalytic DSC and temperature-dependent X-ray diffraction investigations on the cesium dodecahalogeno-closo-dodecaborates Cs2[B12X12] (X = Cl–I) have revealed solid-solid phase transitions from their trigonal room-temperature α-forms (e.g. α-Cs2[B12Cl12]: a = 959.67(3) pm, c = 4564.2(2) pm, Z = 6, space group R$\overline{3}$) into cubic high-temperature modifications. The isotypic title compounds crystallize in the space group Pm$\overline{3}$n (e.g. β-Cs2[B12Cl12]: a = 1051.98(6) pm, Z = 2) with a W3O-type defect structure. The statistic occupation of six possible positions with only four Cs+ cations results in a cation-deficient A2B arrangement for Cs2[B12X12]. Upon cooling the β-phase, a third polymorph was observed, which also crystallizes in the cubic system, but now in the space group Ia$\overline{3}$d (e.g. γ-Cs2[B12Cl12]: a = 2102.2(3) pm, Z = 16), and has to be regarded as a phase with only a partially disordered cation substructure. In this crystal structure the [B12X12]2− anions exhibit a NaTl-type arrangement, in which the Cs+ cations occupy suitable interstices. The phase transitions of the differently halogenated cesium salts follow no specific trend as the transition from the trigonal α- to the cubic β-form occurs at 178 °C for the chlorinated, at 270 °C for the iodinated and at 325 °C for the brominated examples. On further heating however, β-Cs2[B12I12] starts to decompose at 945 °C first, followed by β-Cs2[B12Br12] and β-Cs2[B12Cl12] at 959 °C and 983 °C, respectively.

Nanoscale structure and dynamics of thermoresponsive single-chain nanoparticles investigated by EPR spectroscopy

Soft Matter ◽  
2021 ◽  
Author(s):  
Andreas Roos ◽  
Justus Friedrich Hoffmann ◽  
Wolfgang H Binder ◽  
Dariush Hinderberger
Keyword(s):  
Phase Transitions ◽  
Epr Spectroscopy ◽  
Water Soluble ◽  
Solution Temperature ◽  
Single Chain ◽  
Temperature Dependent ◽  
Critical Solution Temperature ◽  
Structure And Dynamics ◽  
Lcst Behavior ◽  
Nanoscale Structure

We characterize temperature-dependent macroscopic and nanoscopic phase transitions and nanoscopic pre-transitions of water-soluble single chain nanoparticles (SCNPs). The studied SCNPs are based on polymers displaying lower-critical solution temperature (LCST) behavior...

Acoustic Properties of Ho2Si2O7 Single Crystal Investigated by Brillouin Light Scattering

2012 ◽  
Vol 510-511 ◽  
pp. 143-147
Author(s):  
Ghulam Shabbir ◽  
Asghari Maqsood ◽  
Izhar-ul-Haq
Keyword(s):  
Light Scattering ◽  
Elastic Constant ◽  
Single Crystal ◽  
Room Temperature ◽  
Acoustic Properties ◽  
Temperature Dependent ◽  
Hypersonic Velocity ◽  
Brillouin Light Scattering ◽  
Dependent Behavior ◽  
Small Dispersion

Micro-Brillouin light scattering experiments were performed on flux grown D-type (monoclinic, P21/c) Ho2Si2O7 single crystal from room temperature to 850 K. Both the hypersonic velocity (VLA) and related elastic constant (c33) of the longitudinal acoustic phonons propagating along 001-direction showed a small dispersion at T565 K whereas the same could not be observed clearly in attenuation/damping. The overall temperature dependent behavior of elastic constant and hypersonic velocity was attributed to the lattice anharmonicity of the crystal in the investigated temperature range.

Brillouin scattering spectroscopy of ferroelectric and ferroelastic phase transitions

1979 ◽  
Vol 293 (1402) ◽  
pp. 393-405 ◽  
Keyword(s):  
Phase Transitions ◽  
Light Scattering ◽  
Brillouin Scattering ◽  
Structural Phase ◽  
Structural Phase Transitions ◽  
Temperature Dependent ◽  
The Past ◽  
Soft Modes ◽  
Light Scattering Spectroscopy ◽  
Level Of Understanding

Light scattering spectroscopy has played a crucial role in the study of numerous phase transitions and critical phenomena. In the case of structural phase transitions in crystalline solids, high resolution Raman and Brillouin scattering experiments have provided detailed information on the ‘soft modes’, the highly temperature-dependent lattice vibrations whose frequencies fall towards zero at the transition temperature. The condensation of the soft modes precipitates the spontaneous symmetry breaking which inevitably accompanies these transitions. Ferroelectrics comprise a particular class of crystals exhibiting structural phase transitions which have been investigated extensively by light scattering techniques. In addition to numerous soft mode studies, other subtle aspects of these transitions have been investigated by light scattering, including mode interactions and central peaks. In this presentation, the fundamental aspects of structural phase transitions and their relation to light scattering will be reviewed. A number of light scattering studies of ferroelectric crystals spanning the past decade will be summarized and used to illustrate the current level of understanding of these phenomena.

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