Search results for "Electric dipole transition"

Dipole Moments and the Direction of the Transition Dipole Moment of Some Intramolecular Exciplexes

1988

The dipole moments of some intramolecular exciplex systems have been determined from the effect of an electric field on their fluorescence and are compared to those estimated from solvent shift measurements. The charge transfer between the donor and acceptor subunits is between 0.6 and 0.9 of a full charge transfer. The face-to-face type exciplexes show considerable deviations from the general behaviour what might be due to some admixture of locally excited configurations to the exciplex wave function, in this way reducing the dipole moment values and changing the direction of the transition dipole moment.

Roton-roton crossover in strongly correlated dipolar Bose-nonstnon condensates

2011

We study the pair correlations and excitations of a dipolar Bose gas layer. The anisotropy of the dipole-dipole interaction allows us to tune the strength of pair correlations from strong to weak perpendicular and weak to strong parallel to the layer by increasing the perpendicular trap frequency. This change is accompanied by a roton-roton crossover in the spectrum of collective excitations, from a roton caused by the head-to-tail attraction of dipoles to a roton caused by the side-by-side repulsion, while there is no roton excitation for intermediate trap frequencies. We discuss the nature of these two kinds of rotons and the relation to instabilities of dipolar Bose gases. In both regime…

Exploring Quantum Matter with Ultracold Atoms in Optical Lattices

2005

Publisher Summary This chapter explores quantum matter with ultracold atoms in optical lattices. The chapter focuses on bosonic atoms in optical lattices and on the regime where strong correlations between the atoms become important. In the interaction of atoms with coherent light fields, two fundamental forces arise. The Doppler force is dissipative in nature and can be used to efficiently laser cool a gas of atoms and relies on the radiation pressure together with spontaneous emission. The dipole force creates a purely conservative potential in which the atoms can move. No cooling can be realized with this dipole force, however if the atoms are cold enough initially, they may be trapped i…

Electronic Structure of Lr+ (Z = 103) from Ab Initio Calculations

2022

Atoms 10(2), 48 (2022). doi:10.3390/atoms10020048

Radiative lifetimes of Am I atomic levels.

1988

The lifetimes of several atomic levels of Am I that are connected by electric dipole transitions to the ground state have been measured. The Am atoms were excited by light pulses from a cw single-mode dye laser with the aid of an optoacoustic modulator. The decay curve of the delayed emitted photons was measured by counting single photons in the beam-off periods. The lifetimes of 14 levels in the wavelength region between 6405 and 4265 A were measured using Am-metal vapor. The metallic Am was obtained by reducing AmO/sub 2/ with La at 1500 /sup 0/C in a high-vacuum system and collecting Am on a catcher foil. The Am vapor was then produced by controlled reevaporation from the foil at a tempe…

Angular momentum and transition dipole moment

1995

Theoretical study of the electron structure of superheavy elements with an open 6d shell: Sg, Bh, Hs, and Mt

2019

We use recently developed efficient versions of the configuration interaction method to perform {\em ab initio} calculations of the spectra of superheavy elements seaborgium (Sg, $Z=106$), bohrium (Bh, $Z=107$), hassium (Hs, $Z=108$) and meitnerium (Mt, $Z=109$). We calculate energy levels, ionization potentials, isotope shifts and electric dipole transition amplitudes. Comparison with lighter analogs reveals significant differences caused by strong relativistic effects in superheavy elements. Very large spin-orbit interaction distinguishes subshells containing orbitals with a definite total electron angular momentum $j$. This effect replaces Hund's rule holding for lighter elements.

On the magnetic dipole moment of the153Tb ground state

1981

Temperature dependence of the angular distribution anisotropy of the 212·0 keV gamma-ray following the decay of153Tb oriented in a gadolinium host was measured at temperatures from 16 to 70 mK. Magnetic dipole hyperfine splitting parameter a0 for153Tb(Gd) and magnetic dipole moment of the153Tb ground state were estimated to be ¦a0¦≧1·2×10−5 eV and ¦μ¦≧≧3·1 nuclear magnetons, respectively.

Quasirelativistic transition property calculations by the intermediate Hamiltonian method: Electronic transition dipole moments and radiative lifetim…

2001

We present a quasirelativistic method of ab initio calculations on molecular excited states and electronic transition moments within the relativistic effective potential approximation, based on the construction of intermediate Hamiltonians and spin-free one-particle transition density matrices by means of the many-body multipartitioning perturbation theory. The method is applied to describe the electronic transitions involved in the radiative decay of the ${A0}_{u}^{+},$ ${B0}_{u}^{+},$ and ${B1}_{u}$ states of ${\mathrm{Te}}_{2}.$ Good agreement of the computed transition dipole moment functions with their empirical counterparts is achieved. Theoretical radiative lifetime estimates for sev…

Evidence for Three Microscopically Different Kinds of E1 Transitions in Lead-Region Nuclei

1986

One outstanding feature of the shell model in heavy nuclei is that within a main shell the single-particle transitions of electric dipole (E1) character are forbidden. This leads to the experimentally observed fact that the E1 transitions are usually hindered by a factor of about 10 with respect to the Weisskopf estimate. But since there is a dispersion of about two or three orders of magnitude among these hindrance factors, the isomeric E1 transitions have not been used to elucidate the mocroscopic properties of the involved states, as has been done for the E3 transitions of this nuclear region [1]. The E3 transitions often proceed via admixtures of the low-lying collective octupole state,…