Search results for "DIPOLE"
showing 10 items of 982 documents
Vibrational Sum Frequency Generation Spectroscopy of the Water Liquid–Vapor Interface from Density Functional Theory-Based Molecular Dynamics Simulat…
2013
International audience; The vibrational sum frequency generation (VSFG) spectrum of the water liquid-vapor (LV) interface is calculated using density functional theory-based molecular dynamics simulations. The real and imaginary parts of the spectrum are in good agreement with the experimental data, and we provide an assignment of the SFG bands according to the dipole orientation of the interfacial water molecules. We use an instantaneous definition of the surface, which is more adapted to the study of interfacial phenomena than the Gibbs dividing surface. By calculating the vibrational (infrared, Raman) properties for interfaces of varying thickness, we show that the bulk spectra signature…
Molecular structure and electric properties of N -methyl- N -nitroaniline and its derivatives
2001
A comparative study of the molecular structure of N-methyl-N-nitroaniline and its derivatives is carried out employing the Kerr effect and dipole moments methods in combination with the crystallographic analysis. The obtained experimental structural data agree with the quantum-chemical calculations by the B3LYP/6-31G p and MP2/3-21G p methods. The measurement and calculation results are used to draw conclusions about the mutual interaction and role of various substituents to the Nmethyl-N-nitroaniline molecule. q 2001 Elsevier Science B.V. All rights reserved.
Nonadiabatic transitions between lambda-doubling states in the capture of a diatomic molecule by an ion
2008
The low-energy capture of a dipolar diatomic molecule in an adiabatically isolated electronic state with a good quantum number Hund’s coupling case a by an ion occurs adiabatically with respect to rotational transitions of the diatom. However, the capture dynamics may be nonadiabatic with respect to transitions between the pair of the -doubling states belonging to the same value of the intrinsic angular momentum j. In this work, nonadiabatic transition probabilities are calculated which define the -doubling j-specific capture rate coefficients. It is shown that the transition from linear to quadratic Stark effect in the ion-dipole interaction, which damps the T �1/2 divergence of the captur…
Lambda-doublet specificity in the low-temperature capture of NO(X Π21/2) in low rotational states by C+ ions
2009
Following our general approach to Lambda-doubling specificity in the capture of dipolar molecules by ions [M. Auzinsh et al., J. Chem. Phys. 128, 184304 (2008)], we calculate the rate coefficients for the title process in the temperature range 10(-4)<T<10(2) K. Three regimes considered are as follows: (i) nonadiabatic capture in the regime of high-field Stark effect with respect to the Lambda-doubling components, (10(-1)<T<10(2) K), (ii) adiabatic capture in the regime of intermediate Stark effect (10(-3)<T<10(-1) K), and (iii) adiabatic capture in the limit of very low temperatures (T<<10(-3) K) in the regime of quadratic Stark effect with respect to the Lambda-doubling and hyperfine compo…
Nuclear moments and the change in the mean square charge radius of neutron deficient thallium isotopes
1992
The hyperfine structure, isotope and isomeric shifts in the atomic transition 6p 2 P 3/2−7s 2 S 1/2, λ=535 nm have been measured for theI=7 andI=2 states of190, 192, 194, 196Tl; theI=1/2 andI=9/2 states of191Tl and the I=7 isomer of188Tl. The thallium isotopes were prepared as fast atomic beams at the GSI on-line mass separator following fusion reactions and — in some cases — subsequentβ-decay. The nuclear dipole moments, electric quadrupole moments and the change in the nuclear mean square charge radius are evaluated. Theuu-isotopes show an isomeric shift which changes sign between192Tl and194Tl.
Studies of host-guest thin films of corona-poled betaine-type polar molecules by kelvin probe technique and atomic force microscopy
2004
In this work betaine-type molecules were investigated. As a result of the asymmetry of charge distribution, molecules possess in the ground state a considerable permanent dipole moment. The decay of surface potential of poled polymer films is dependent at least on two relaxation processes. The influence of glass transition of PMMA on thermal dependence of the surface potential is shown. The transition temperature, where no changes of the surface potential appeared, is related to glass transition temperature of the host-guest system. The topography of the film surface was obtained by AFM.
Studies on proton acceptor ability of SOx-containing compounds
1995
Abstract IR spectra, dipole moments and molar Kerr constants of complexes of phenols with compounds containing SO x groups were studied to establish the structure of the complexes and the parameters characterizing the proton acceptor capability of these compounds. ( μ H , Δ ( mK ), log K and δ 0 ). It has been suggested that the new parameter Δ ( mK ) — the structural additive difference of the molar Kerr constant — makes it possible to determine changes of polarity and polarizability of the systems during complex formation.
Studies on the proton acceptor ability of phosphoryl compounds
1996
Abstract Dipole moments and molar Kerr constants of complexes of phenols with phosphoryl compounds were studied to establish the structure of complexes and parameters characterizing the proton acceptor ability of these compounds. The structures of these complexes and parameters ( μ H , Δ ( mk ) S , log K and δ 0 ) were established. It has been suggested that a new parameter Δ ( mK ) S — structural additive difference of the molar Kerr constant — makes it possible to determine changes of polarity and polarizability of the systems during complex formation.
Measurement of the Permanent Electric Dipole Moment of the $^{129}$Xe Atom
2019
We report on a measurement of the $CP$-violating permanent electric dipole moment (EDM) of the neutral $^{129}\mathrm{Xe}$ atom. Our experimental approach is based on the detection of the free precession of co-located nuclear spin-polarized $^{3}\mathrm{He}$ and $^{129}\mathrm{Xe}$ samples. The EDM measurement sensitivity benefits strongly from long spin coherence times of several hours achieved in diluted gases and homogeneous weak magnetic fields of about 400 nT. A finite EDM is indicated by a change in the precession frequency, as an electric field is periodically reversed with respect to the magnetic guiding field. Our result $(\ensuremath{-}4.7\ifmmode\pm\else\textpm\fi{}6.4)\ifmmode\t…
Probing Lorentz invariance and other fundamental symmetries in3He/129Xe clock-comparison experiments
2011
We discuss the design and performance of a very sensitive low-field magnetometer based on the detection of free spin precession of gaseous, nuclear polarized 3He or 129Xe samples with a SQUID as magnetic flux detector. Characteristic spin precession times T*2 of up to 60 h were measured in low magnetic fields (about 1μT) and in the regime of motional narrowing. With the detection of the free precession of co-located 3He/129Xe nuclear spins (clock comparison), the device can be used as ultra-sensitive probe for non-magnetic spin interactions, since the magnetic dipole interaction (Zeeman-term) drops out in the weighted frequency difference, i.e., Δω = ωHe− γHe/γXe·ωXe. We report on searches …