Search results for "Multiplet"
showing 10 items of 65 documents
The influence of the dynamics of ionic multiplets onto electronic transport properties of heavy-fermion systems: a semi-phenomenological approach
2001
We present calculations of the electronic transport properties of heavy-fermion systems within a semi-phenomenological approach to the dynamical mean field theory. In this approach the dynamics of the Hund's rules 4f (5f )-ionic multiplet split in a crystalline environment is taken into account. Within the scope of this calculation we use the linear response theory to reproduce qualitative features of the temperature-dependent resistivity and hall conductivity, the magneto-resistivity and the thermoelectric power typical for heavy-fermion systems. The model calculations are directly compared with experimental results on CeCu2Si2.
Defect states and excitations in a Mott insulator with orbital degrees of freedom: Mott-Hubbard gap versus optical and transport gaps in doped systems
2013
We address the role played by charged defects in doped Mott insulators with active orbital degrees of freedom. It is observed that defects feature a rather complex and rich physics, which is well captured by a degenerate Hubbard model extended by terms that describe crystal-field splittings and orbital-lattice coupling, as well as by terms generated by defects such as the Coulomb potential terms that act both on doped holes and on electrons within occupied orbitals at undoped sites. We show that the multiplet structure of the excited states generated in such systems by strong electron interactions is well described within the unrestricted Hartree-Fock approximation, once the symmetry breaki…
Hyperfine structure of the 3d34s4p6G multiplet of atomic vanadium
2011
The spectrum of atomic vanadium was recorded using high-resolution Fourier transform spectroscopy with optical bandpass filters in the wavelength range from 360 to 500 nm. Vanadium atoms are produced and excited in a hollow-cathode discharge. The main focus lies on the determination of the magnetic dipole hyperfine constants A of the lowest multiplet of odd parity, the 6G of the configuration 3d34s4p, the hyperfine structure (HFS) of which was unknown to date. The HFS of the lines, connecting this multiplet with the multiplets 3d34s5s 6F, 3d34s4d 6H and 3d34s4d 6G, was observed and analysed. New results are presented for all six levels belonging to 3d34s4p 6G as well as for seven high-lying…
Measurements and calculations of Stark broadening parameters for the N I multiplet (1D)3s2D–(1D)3p2Do
2014
Calculations of line broadening parameters of a doubly excited N I transition, based on atomic structure data (taken from the literature), are reported. The obtained results were used for a critical analysis of formerly published experimental data, based on spectra measured in our laboratory. These measured spectra were then again analyzed and new broadening parameters were determined and compared with results of calculations.
Stark-Broadening Studies of N(I) Multiplet 3p 4P o–3d 4D at 1052.630 nm
2020
Stark-broadening studies of the N(I) multiplet 3p 4P o –3d 4D are reported. Our experimental electron impact widths of spectral lines are compared with the results of our calculations: (i) according to the standard impact theory of Griem with modification, (ii) using a computer simulation method which is based on numerical N-body code (CSM). Line shape measurements were performed using a wallstabilized arc. The radiation of the plasma emitted from homogenous plasma layers was measured using a grating spectrometer equipped with a two-dimensional detector.
2p x-ray absorption spectroscopy of 3d transition metal systems
2021
Abstract This review provides an overview of the different methods and computer codes that are used to interpret 2p x-ray absorption spectra of 3d transition metal ions. We first introduce the basic parameters and give an overview of the methods used. We start with the semi-empirical multiplet codes and compare the different codes that are available. A special chapter is devoted to the user friendly interfaces that have been written on the basis of these codes. Next we discuss the first principle codes based on band structure, including a chapter on Density Functional theory based approaches. We also give an overview of the first-principle multiplet codes that start from a cluster calculati…
One-loop renormalization of Resonance Chiral Theory: scalar and pseudoscalar resonances
2005
We consider the Resonance Chiral Theory with one multiplet of scalar and pseudoscalar resonances, up to bilinear couplings in the resonance fields, and evaluate its beta-function at one-loop with the use of the background field method. Thus we also provide the full set of operators that renormalize the theory at one loop and render it finite.
Form-factors and current correlators: chiral couplingsL10r(μ) andC87r(μ) at NLO in 1/NC
2008
Using the resonance chiral theory Lagrangian, we perform a calculation of the vector and axial-vector two-point functions at the next-to-leading order (NLO) in the 1/N-C expansion. We have analyzed these correlators within the single-resonance approximation and have also investigated the corrections induced by a second multiplet of vector and axial-vector resonance states. Imposing the correct QCD short-distance constraints, one determines the difference of the two correlators Pi(t) equivalent to Pi(VV)(t)-Pi(AA)(t) in terms of the pion decay constant and resonance masses. Its low momentum expansion fixes then the low-energy chiral couplings L 1 0 and C 8 7 at NLO, keeping full control of t…
Quark structure of the $$\chi _{\mathrm{c}}(3P)$$ and X(4274) resonances and their strong and radiative decays
2020
AbstractWe calculate the masses of $$\chi _{\mathrm{c}}(3P)$$χc(3P) states with threshold corrections in a coupled-channel model. The model was recently applied to the description of the properties of $$\chi _{\mathrm{c}}(2P)$$χc(2P) and $$\chi _{\mathrm{b}}(3P)$$χb(3P) multiplets (Ferretti and Santopinto in Phys Lett B 789:550, 2019]. We also compute the open-charm strong decay widths of the $$\chi _{\mathrm{c}}(3P)$$χc(3P) states and their radiative transitions. According to our predictions, the $$\chi _{\mathrm{c}}(3P)$$χc(3P) states should be dominated by the charmonium core, but they may also show small meson-meson components. The X(4274) is interpreted as a $$c {{\bar{c}}}$$cc¯$$\chi …