Microreflectance Infrared Study of Bis(Ethylenedithio)-Tetrathiafulvalene (BEDT-TTF or ET) Salts

1992 ◽  
Vol 46 (10) ◽  
pp. 1520-1524 ◽  
Author(s):  
John R. Ferraro ◽  
H. Hau Wang ◽  
Myung-Hwan Whangbo ◽  
Phil Stout
Keyword(s):  
Infrared Spectra ◽  
Polarized Light ◽  
Structural Disorder ◽  
Donor Molecule ◽  
Infrared Study ◽  
Unpolarized Light ◽  
Β Phase ◽  
Light Vector ◽  
Deuterium Analog

For several β- and κ-phase salts of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF or simply ET) and its deuterium analog d8-ET, microreflectance infrared spectra were obtained by employing polarized and unpolarized light, and their vibronic regions were examined. These salts exhibit a strong vibronic absorption under polarized light. The vibronic absorption of the β-phase salts has a much stronger polarization-dependency than that found for the κ-phase salts. For the β-phase salts, the optimum vibronic absorption occurs when the polarized light vector is parallel to their donor-molecule stacking direction. Among the ET salts without structural disorder, the highest C-C-H bending frequency for the superconductors is lower than ∼1320 cm−1 while that for the non-superconductors is higher than ∼1320 cm−1.

scholarly journals Studies on the electrostatic effects of stretched PVDF films and nanofibers

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yixuan Lin ◽  
Yuqiong Zhang ◽  
Fan Zhang ◽  
Meining Zhang ◽  
Dalong Li ◽  
...  
Keyword(s):  
Vinylidene Fluoride ◽  
Polarized Light ◽  
Transition Process ◽  
Open Circuit ◽  
Wearable Electronics ◽  
Energy Harvesters ◽  
Β Phase ◽  
Poly Vinylidene Fluoride ◽  
Piezoelectric Effects ◽  
Energy Harvesting Devices

AbstractThe electroactive β-phase in Poly (vinylidene fluoride, PVDF) is the most desirable conformation due to its highest pyro- and piezoelectric properties, which make it feasible to be used as flexible sensors, wearable electronics, and energy harvesters etc. In this study, we successfully developed a method to obtain high-content β-phase PVDF films and nanofiber meshes by mechanical stretching and electric spinning. The phase transition process and pyro- and piezoelectric effects of stretched films and nanofiber meshes were characterized by monitoring the polarized light microscopy (PLM) images, outputting currents and open-circuit voltages respectively, which were proved to be closely related to stretching ratio (λ) and concentrations. This study could expand a new route for the easy fabrication and wide application of PVDF films or fibers in wearable electronics, sensors, and energy harvesting devices.

Conversion of unpolarized light to polarized light with greater than 50% efficiency by photorefractive two-beam coupling

2000 ◽  
Vol 25 (4) ◽  
pp. 257 ◽  
Author(s):  
John E. Heebner ◽  
Ryan S. Bennink ◽  
Robert W. Boyd ◽  
R. A. Fisher
Keyword(s):  
Polarized Light ◽  
Unpolarized Light ◽  
Beam Coupling

Investigation on β-Polypropylene/Talc Composites

2012 ◽  
Vol 182-183 ◽  
pp. 259-264
Author(s):  
Jia Wei Duan ◽  
Qiang Dou
Keyword(s):  
Polarized Light ◽  
Nucleating Agent ◽  
Mechanical Tests ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Melt Compounding ◽  
Β Phase ◽  
Α Phase ◽  
Melting And Crystallization

In this study polypropylene (PP) composites containing β-nucleating agent (NT-C) and talc filler were prepared by melt compounding. The melting and crystallization behavior, morphology and mechanical properties of the composites were studied by means of differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD), polarized light microscopy (PLM) and mechanical tests. The results indicate that talc suppresses the formation of β phase, but promotes the formation of α phase. The Izod notched impact strength and tensile strength of β-PP/talc composites are superior to those of PP/talc composites, indicating an outstanding balance of stiffness and toughness of β-PP/talc composites.

Shade-seeking behaviour under polarized light by the brittlestar Ophioderma Brevispinum (Echinodermata: Ophiuroidea)

1999 ◽  
Vol 79 (4) ◽  
pp. 761-763 ◽  
Author(s):  
Sönke Johnsen ◽  
William M. Kier
Keyword(s):  
Ultraviolet Radiation ◽  
Random Distribution ◽  
Polarized Light ◽  
Solar Ultraviolet Radiation ◽  
Unpolarized Light ◽  
Linearly Polarized ◽  
Solar Ultraviolet ◽  
Marine Laboratory

The effect of polarized light on the shade-seeking behaviour of the ophiuroid Ophioderma brevispinum was investigated at the Keys Marine Laboratory, Long Key, Florida, USA. Animals were collected and placed in a partially shaded arena. When the arena was illuminated with unpolarized light, the number of animals settling under the shaded portion of the arena was not significantly different from random (N=30, P>0.3). When the arena was illuminated with linearly polarized light, the number of animals settling in the shaded portion of the arena was approximately double what would be expected in a random distribution (N=30, P<0.001). The results are further evidence that O. brevispinum is sensitive to polarized light and are consistent with the hypothesis that polarized light may be used by the animals as an indicator of harmful levels of solar ultraviolet radiation.

A Fourier transform infrared study of the electrophilic attack at the N7-site of guanosine-5′-monophosphate

1984 ◽  
Vol 62 (2) ◽  
pp. 266-272 ◽  
Author(s):  
H. A. Tajmir-Riahi ◽  
T. Theophanides
Keyword(s):  
Fourier Transform ◽  
Infrared Spectra ◽  
Fourier Transform Infrared ◽  
Divalent Metal ◽  
Ring System ◽  
Disodium Salt ◽  
Divalent Metal Ions ◽  
Electrophilic Attack ◽  
Infrared Study ◽  
Spectral Changes

Fourier transform infrared spectra of several N7-bound cations of guanosine-5′monophosphate disodium salt (5′-GMPNa2), such as N7-H+GMP, N7-MeGMP, and N7-MGMP, where Me = CH3+ and M = divalent metal ions, Cd, Mn, Co, Ni, Cu, Pt, and Mg, have been recorded and a correlation between the spectral changes and the nature of the electrophile (H+, CH3+, and M2+) bound has been established. Spectroscopic evidence shows that methylation of the N7-position of 5′-GMPNa2 causes larger perturbation on the guanine ring system than protonation or metalation, in the order Me+ > H+ > M2+. The effect of an N7-electrophilic attack on the vibrational frequencies of the purine, the sugar, and the phosphate group is discussed.

Infrared spectra in polarized light of crystalline C5H5NiNO and C5D5NiNO

1973 ◽  
Vol 29 (2) ◽  
pp. 277-284 ◽  
Author(s):  
A. Poletti ◽  
R. Cataliotti ◽  
G. Paliani
Keyword(s):  
Infrared Spectra ◽  
Polarized Light

A Low Temperature Infrared Study of Self-association in Thiols

1972 ◽  
Vol 50 (22) ◽  
pp. 3594-3600 ◽  
Author(s):  
R. Bicca de Alencastro ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bonding ◽  
Low Temperature ◽  
Infrared Spectra ◽  
Low Temperatures ◽  
Infrared Study ◽  
Text Type ◽  
Stretching Vibration ◽  
Aliphatic Thiols ◽  
Self Association ◽  
Associated Species

The infrared spectra of several aliphatic thiols and of benzenethiol were measured between 2400 and 2700 cm−1, and 4800 and 5300 cm−1 in a 1:1 mixture of CCl3F and C2F4Br2, at temperatures ranging from 20 to −190 °C. Dimerization takes place at low temperatures and more highly associated species also appear. Free S—H groups are present in the solutions as well as in the pure liquids, even at the lowest temperatures. The association is of the [Formula: see text] type in aliphatic thiols; both [Formula: see text] and [Formula: see text] bonds are found in the case of benzenethiol and α-toluenethiol. Hydrogen bonding has little effect on the anharmonicity of the S—H stretching vibration.

An infrared study of interactions in the system sodium tert-butoxide-tetrahydrofuran

1989 ◽  
Vol 54 (2) ◽  
pp. 308-315
Author(s):  
Libor Matějka ◽  
Lubomír Lochmann ◽  
Pavel Schmidt
Keyword(s):  
Stability Constant ◽  
Infrared Spectra ◽  
Adduct Formation ◽  
Large Excess ◽  
Infrared Study ◽  
Hydrocarbon Solvents ◽  
The Stability ◽  
System Sodium

The adduct of sodium tert-butoxide (t-BuONa) with tetrahydrofuran (THF) was studied by measuring changes of infrared spectra in the range 900-1100 cm-1. Alkoxide autoassociation and solvation of this associate by tetrahydrofuran play a role in adduct formation. In hydrocarbon solvents in the presence of minor amounts of THF, higher t-BuONa associates are dissociated, the preffered form being a tetramer solvated by three THF molecules. At large excess of THF, the tetramer is solvated by four THF molecules. The stability constant of the adduct, referred to one Na-O bond, is 5.01.

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