Ab initiocalculation of frequency-dependent atomic dipole polarizability

Abstract

The polarized orbitals produced by simultaneous optimization of both bound and continuum multiconfiguration Hartree-Pock wave functions at each kinetic energy of the scattering electron in lowenergy electron-atom collisions are used to calculate the frequency-dependent dipole polarizability of the ground state of atomic oxygen. Excellent agreement is obtained with experiment and other theoretical calculations, indicating that this ab initio approach is a powerful tool for determining accurate frequency-dependent atomic dipole polarizabilities.

Static response properties of second-period atoms: coupled cluster calculations

“…The CEPA-SD values of Jaquet et al (1992) are in very close agreement with our CCSD(T) values, whereas the MRDCI results of Rérat et al (1997) seem to be too low. The MCHF results of Saha (1993) are poor; his α is of the opposite sign to that obtained by all other calculations. Table 6 shows that the MRCI values of Nelin et al (1982) are rather low for fluorine.…”

Measurement of light shifts at two off-resonant wavelengths in a single trappedBa+ion and the determination of atomic dipole matrix elements

“…Adding statistical (one standard deviation) and systematic errors (discussion to follow) together in quadrature, we find that R(514.531 nm) = −11.494( 13), (10) R(1111.68 nm) = +0.4176 (8). (11) The quoted error in the latter result has been χ 2corrected by a factor of 1.3 to account for unexplained excess scatter in the data; the reduced χ 2 of the result at 514.531 nm is 1.0.…”

“…Although the atomic structure of singly-ionized barium is generally well understood, and a number of precise calculations of transition matrix elements have been carried out in recent years ( [8,9,11,12], among others), precise measurements of these matrix elements are relatively few. Among the low-lying electric dipole transitions, only the 6S||er||6P matrix element has been measured with an accuracy approaching 1%, while the 5D||er||4F matrix element is unknown in the literature (see Table I).…”

“…The key idea is to determine the ratio of light shifts simultaneously measured in two atomic states, thereby eliminating the need to precisely know or control the light shift laser intensity. Our measurements place constraints on the Ba + matrix elements that can test modern atomic theories, such as the coupled-cluster method, and ab initio techniques ( [8,11,12], for example).…”

The Stark effect of the excited1B2state of SO2and manipulation of dissociation channels

“…The shift of the levels of the oxygen atom due to the Stark effect is approximately −α 0 E 2 /2. With α = 0.77 Å3 as given by Saha [29], we only expect a negligible shift of a few megahertz.…”