Lithium in strong magnetic fields

Abstract

The electronic structure of the lithium atom in a strong magnetic field 0 <= gamma <= 10 is investigated. Our computational approach is a full configuration interaction method based on a set of anisotropic Gaussian orbitals that is nonlinearly optimized for each field strength. Accurate results for the total energies and one-electron ionization energies for the ground and several excited states for each of the symmetries ^20^+, ^2(-1)^+, ^4(-1)^+, ^4(-1)^-, ^2(-2)^+, ^4(-2)^+, $^4(-3)^{+}$ are presented. The behaviour of these energies as a function of the field strength is discussed and classified. Transition wave lengths for linear and circular polarized transitions are presented as well.Comment: 12 pages, 13 figures, accepted for publication in Phys. Rev.

Comparative studies of density-functional approximations for light atoms in strong magnetic fields

“…For Z 4, our HGGA results agree better with correlated wave-function results [19][20][21][22][23][24][25][26][27] than those from other DFT approximations we investigated. For Z 5, we did not find correlated wave-function results with which to compare.…”

“…As far as we can tell, there is no prior application of density-gradient-dependent functionals to atoms in a strong B field. In the broader context, since DFT calculations in principle include electron correlation, it also is appropriate to compare our nB-DFT results with those from correlated wave-function methods [19][20][21][22][23][24][25][26][27].…”

“…, with π z j = 0,1. AGTO basis sets have been used in several studies of atoms in strong B fields [20,21,24,25,27] because of their flexibility in describing elongation of the electron orbitals and densities along the B-field direction. With no unique way to determine the basis exponents, α j and β j , a physically sound prescription must be developed.…”

“…with extremely rich, aspherical basis sets and several xc functionals, including one combination which apparently has gone unexplored heretofore. We take advantage of the availability of several Hartree-Fock (HF) [10][11][12][13][14][15][16][17][18] and correlated wave-function studies of at least a few light atoms in an external B field [19][20][21][22][23][24][25][26][27] and of quantum Monte Carlo (QMC) studies [28,29] for comparisons. In particular, comparison of our HF calculations with prior ones provides calibration of the accuracy of our techniques, while comparison with the QMC results gives a measure of absolute accuracy and trends in accuracy for the various DFT approximations.…”

Atomic ground states in strong magnetic fields: Electron configurations and energy levels

“…In another Hartree-Fock approach, Thirumalai and Heyl [13] obtained quite accurate values for the low-lying levels of helium, whereas, Becken et al [14] and Becken and Schmelcher [15][16][17] used a highly precise full configuration-interaction (CI) method to analyze a large amount of helium states and transitions in a wide range of magnetic-field strengths. Low-lying states of lithium and beryllium have been studied with high accuracy using modified freezing full-core methods [18,19], configuration-interaction methods [20,21], and methods based on an anisotropic Gaussian basis set [22][23][24].…”