Influence Of Dipole Moment Research Articles

Influence of dipole moment on the VOC sensing properties of BiFeO3 microspheres: Addressing the selectivity towards acetone

The selectivity of a chemi-resistive sensor towards a particular gas/vapor depends on various factors and needs to be explained more precisely. Herein, the selective detection of acetone by hydrothermally prepared BiFeO3 microspheres has been explained correlating the dipole moment of tested volatile organic compounds (VOCs) with the sensing properties followed by the dipole-dipole interaction between sensing material and target VOCs. Acetone with the highest dipole moment (2.91 D) compared to other interfering vapors shows the highest response of 10±1 for 50 ppm operating at 400 °C governed by the strongest dipole-dipole interaction. Moreover, a moderate degree of repeatability shown in 7 cycles, long-term stability tested for 90 days along with the microstructural and compositional stability tested before and after the sensing tests, and consistency in sensing performance even in humid atmospheres point toward the potential of the prepared material as a reliable acetone sensor along with proper validation of its selectivity issue.

Information processing and thermodynamic properties of microtubules

The Shannon entropy dependence on temperature, dipole moment and thermodynamic properties of microtubules (MTs) have been investigated using the Landau–Ginzburg phenomenological theory through continuum Boltzmann distribution function. By minimising the loss in energy, we found that there is a possibility that MTs formed from the heterodimers can process information over a long time at higher temperature. We also found that multiple heterodimers under the influence of dipole moment, has the tendency to process information whenever the amount of information stored or transferred decreases with increasing electronegativity of the system. We analyse the dynamic instability phenomenon that infinitely occurs in polymerisation and depolymerisation processes in MTs. Also, under physiological conditions, temperature dependence of thermodynamic properties was investigated and our results exhibited critical behaviour of heat capacity and chemical potential giving room for phase transitions around 302 K.

Discotic hexa-peri-hexabenzocoronenes with strong dipole: synthesis, self-assembly and dynamic studies

Strong dipole moments have been built into two hexa-peri-hexabenzocoronene (HBC) derivatives (1 and 2) originating from the push-pull structure of the molecules with one electron-donating and one electron-withdrawing substituent. The influence of dipole moment on the self-assembly of HBCs in solution and in bulk has been investigated.

The influence of dipole moments on the mechanism of electron transfer through helical peptides

The life time of aromatic radical cations is limited by reactions like β-elimination, dimerization, and addition to the solvent. Here we show that the attachment of such a radical cation to the C-terminal end of an α-/3(10)-helical peptide further reduces its life time by two orders of magnitude. For PPII-helical peptides, such an effect is only observed if the peptide contains an adjacent electron donor like tyrosine, which enables electron transfer (ET) through the peptide. In order to explain the special role of α-/3(10)-helical peptides, it is assumed that the aromatic radical cation injects a positive charge into an adjacent amide group. This is in accord with quantum chemical calculations and electrochemical experiments in the literature showing a decrease in the amide redox potentials caused by the dipole moments of long α-/3(10)-helical peptides. Rate measurements are in accord with a mechanism for a multi-step ET through α-/3(10)-helical peptides that uses the amide groups or H-bonds as stepping stones.

Laterally Resolved Orientation and Film Thickness of Polar Metal Chlorine Phthalocyanines on Au and ITO

The molecular orientation and homogeneity of gallium(III) and aluminum(III) chlorine phthalocyanine (GaClPc and AlClPc) are studied on flat (gold single crystal, Au(100)) and rough surfaces (indium tin oxide, ITO) by Raman spectroscopy in combination with X-ray absorption spectroscopy (XAS) in detail. In the case of Raman spectroscopy, Euler angles are used to describe the geometry while Raman imaging provides insight into homogeneity. For XAS, synchrotron radiation is applied to study the angle dependence of the excitation structure. On Au(100) the molecules are highly ordered and tend to align parallel to the surface (lying) with a layer by layer growth mode. Contrarily, on technically relevant substrates, as in the case of ITO, less ordered films due to the roughness of the surface nature are present. The results are discussed in relation to the substrate's nature and the influence of dipole moments.

Influence of dipole moments on light-emitting features of cardo-type 1 H-pyrazolo[3,4- b]quinolines

Several 1 H-pyrazolo[3,4- b]quinoline derivatives were synthesized from 9,9′-di( p-aminophenyl)fluorene as possible dye chromophore for the organic light-emitting diodes. All the compounds exhibit strong fluorescence in solution and in solid state as well. The maximally achieved brightness was 65 Cd/m 2 and spectral range of electroluminescence (EL) covers the wavelength ranges from 420 up to 470 nm. The prepared compounds were used as dye luminophores in poly( N-vinylcarbazole) (PVK) matrix for single-layer EL light-emitting device. Principal goal of the work consists in an establishment of a possibility to operate by their light-emitting features (spectral positions of emitting lines, efficiency of electroluminescence, brightness, etc.) by appropriate changes of state dipole moments of the particular chromophore determined by semi-empirical quantum chemical calculations. The principal physical mechanism of such effects is explained within dipole–dipole interactions between the dye chromophores and PVK polymer chains.

Investigation of order and optical switching in ultrathin films of azo-containing materials using dielectric spectroscopy

The azobenzene group is known for its cis-trans isomerism under irradiation with blue and ultraviolet light, respectively. New organic materials with different dipole moments were used to investigate the effect of molecular parameters on supramolecular film properties of ultrathin films. The influence of dipole moment and the molecular environment of the materials on the switching process is examined by means of dielectric spectroscopy.

Infrarot-Bandenform adsorbierter Moleküle in Hohlräumen von Zeolithen des Typs A

A correlation between frequency shift and half width of the infrared bands of some linear and bent three-atomic molecules adsorbed on zeolites NaA and NaCaA has been observed. The influence of dipole moment, translational energy, sorption site and parallels with NMR investigations are discussed.

Electrochemical studies on the adsorption of amino acids in relation to the compatibility of prosthetic materials and the human body.

AbstractThe Lippman electrocapillary method was used to survey the adsorption behavior of 25 amino acids at the mercury‐solution interface. The amount of surface excess of adsorbed amino acid (Γ;), as evidenced by lowering of interfacial tension, was found to increase with the number of double bonds and/or additional nitrogen atoms which provide electron pairs. No influence of dipole moment on adsorption was observed. Adsorption was more extensive at potentials positive to the potential of zero charge, indicating a possible electrontransfer adsorption mechanism, i.e., a sharing π‐electrons rather than dipole interaction with the metal. These results are consistant with the enhanced adsorption of proteins at anodic potentials since the side groups extending from peptide linkages on a given protein are the R groups of various amino acids.

The Far Ultraviolet Absorption Spectra of Formaldehyde and the Alkyl Derivatives of H2O and H2S

The absorption spectra of formaldehyde and of compounds of the type HOH, ROH, ROR and HSH, RSH, RSR have been observed in the region 2300–1000A. An analysis of the spectrum of formaldehyde yields a value of 10.83±0.01 volts for the first ionization potential of the C=O bond and about 164 Cal./mole for the strength of this bond. The spectra of the alkyl derivatives of H2S are all shown to be shifted to the long wavelength region relative to those of H2O. Rough estimates of their ionization potentials are given and the influence of dipole moment on the ultraviolet absorption spectra and ionization potentials of polyatomic molecules is discussed.