Search results for "Hamiltonian"
showing 10 items of 662 documents
High-resolution spectroscopy and preliminary global analysis of C–H stretching vibrations of C2H4 in the 3000 and 6000cm−1 regions
2010
Abstract Ethylene (ethene, H2C=CH2) is a naturally occurring compound in ambient air that affects atmospheric chemistry and global climate. The C2H4 spectrum is available in databases only for the 1000 and 3000 cm−1 ranges. In this work, the ethylene absorption spectrum was measured in the 6030–6250 cm−1 range with the use of a high resolution Bruker IFS 125HR Fourier-spectrometer and a two-channel opto-acoustic spectrometer with a diode laser. As a secondary standard of wavelengths, the methane absorption spectrum was used in both cases. A preliminary analysis was realized thanks to the tensorial formalism developed by the Dijon group that is implemented in the XTDS software package [39] .…
Highly-spherical Top Data System (HTDS) software for spectrum simulation of octahedral XY6 molecules
2000
Abstract The Spherical Top Data System (STDS) program suite developed in Dijon has been extended into two directions. First, the vibrational extrapolation is now possible for any kind of polyad scheme, this one being fully specified in the input parameters of the programs for hamiltonian and transition moment model calculations. This was not the case of the preceding version which was based on the polyad scheme of methane. Secondly, it is now possible to study any band and polyad of XY 6 molecule for which a complete treatment in the O h group is made. Up to now, only some vibrational levels of these molecules ( F 1u levels in particular) could be studied using equivalences with the T d gro…
top data system ( TDS) software for infrared spectrum simulation of asymmetric molecules: some improvements to the TDS packages
2005
Abstract The spherical top data system (STDS) program suite developed in Dijon has been extended with the aim of studying any rovibrational band or polyad of XY 2 Z 2 ( C 2 v ) asymmetric top molecules. We work in the O ( 3 ) ⊃ T d ⊃ C 2 v chain because these species result from the substitution of two ligands of a corresponding “parent” spherical top and thus are relatively close to tetrahedral symmetry. The choice of this group chain has consequences on the method used to specify the input parameters of the programs for Hamiltonian and transition moment model calculations. One example concerning the ground state of the SO2F2 quasi-spherical molecule is presented. As before, this suite con…
C4v Top Data System (C4v TDS) software for infrared spectrum simulation of XY5Z symmetric molecules
2002
Abstract The Highly spherical Top Data System program suite developed in Dijon has been extended in the aim of studying any rovibrational band or polyad of XY5Z (C4v) symmetric top molecules. We work in the O(3)⊃Oh⊃C4v chain because most of these species result from the substitution of one ligand of the corresponding spherical tops and thus are relatively close to octahedral symmetry. The choice of this group chain has consequences in the way in which it is used to specify the input parameters of the programs for Hamiltonian and transition moment model calculations. One example concerning the ν1/ν8 dyad of the SF 5 35 Cl molecule is presented. As before, this suite consists of a series of F…
New assignments in the 2μm transparency window of the 12CH4 Octad band system
2013
Abstract This paper reports new assignments of rovibrational transitions of 12 CH 4 bands in the range 4600–4887 cm −1 which is usually referred to as a part of the 2 μm methane transparency window. Several experimental data sources for methane line positions and intensities were combined for this analysis. Three long path Fourier transform spectra newly recorded in Reims with 1603 m absorption path length and pressures of 1, 7 and 34 hPa for samples of natural abundance CH 4 provided new measurements of 12 CH 4 lines. Older spectra for 13 CH 4 (90% purity) from JPL with 73 m absorption path length were used to identify the corresponding lines. Most of the lines in this region belong to th…
Linear response in multipolar glasses
1988
We consider the unified hamiltonian with a bilinear coupling, describing the Ising-, vector-, Potts-, octupolar-glass and other glasses [1, 2]. We systematically derive the response to a homogeneous tensor-field as well as the response to an inhomogeneous random tensor-field. We investigate the overlap distribution function and its first and second moment. In all these considerations, we recover the results of the Ising spin glass for sufficiently symmetric multipolar glasses, but we also obtain differnt results for less symmetric glasses.
The Stochastic Limit of the Fröhlich Hamiltonian: Relations with the Quantum Hall Effect
2003
We propose a model of an approximatively two-dimensional electron gas in a uniform electric and magnetic field and interacting with a positive background through the Fröhlich Hamiltonian. We consider the stochastic limit of this model and we find the quantum Langevin equation and the generator of the master equation. This allows us to calculate the explicit form of the conductivity and the resistivity tensors and to deduce a fine tuning condition (FTC) between the electric and the magnetic fields. This condition shows that the x-component of the current is zero unless a certain quotient, involving the physical parameters, takes values in a finite set of physically meaningful rational number…
Solution of the fully-mixed-state problem: Direct deperturbation analysis of theAΣ+1–bΠ3complex in a NaCs dimer
2009
Laser-induced fluorescence (LIF) spectra $(4)\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}^{+}\ensuremath{\rightarrow}A\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}^{+}--b\phantom{\rule{0.2em}{0ex}}^{3}\ensuremath{\Pi}$ and collisionally enhanced $A\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}^{+}--b\phantom{\rule{0.2em}{0ex}}^{3}\ensuremath{\Pi}\ensuremath{\rightarrow}X\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}^{+}$ LIF spectra measured by Fourier transform spectrometer with the resolution of $0.03--0.05\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ provided about 1160 term values of the $e$-symmetry rovibronic levels of the fully mixed $A\phantom{\rule{…
Laser driven structured quantum rings
2015
In this work we study harmonic emission from structured quantum rings (SQRs). In SQRs, electrons trapped in two-dimensional structures are further confined by an external potential composed of N scattering centers arranged on a circle. We build a suitable one-dimensional model Hamiltonian describing this class of systems and analytically solve the associated Schödinger equation. We find that the solution can be expressed in terms of Mathieu functions and focus on the specific case of N = 6. By exactly solving the time-dependent Schödinger equation, we then show how the harmonic response to linearly polarized lasers strongly depends on the ring physical parameters. The results illustrate how…
First Assignment and Line Strengths of the 4ν4 Band of 12CH4 near 1.9 μm
2001
Abstract The investigation of the methane spectrum in the region 1.6–2 μm has provided the first assignment and analysis of the 4ν 4 band near 1.9 μm. Hamiltonian and dipole moment operators written in tetrahedral formalism and adapted to the extrapolation method have been used to fit the spectra recorded at the Kitt Peak National Observatory/National Solar Observatory. Nearly 190 line positions and 160 measured intensities have been modeled with standard deviations of 0.107 cm −1 and 18.5%, respectively.