Energy levels and lifetimes of Gd IV and enhancement of the electron dipole moment

We have calculated energy levels and lifetimes of 4f7 and 4f6 5d configurations of Gd IV using Hartree-Fock and configuration interaction methods. This allows us to reduce significantly the uncertainty of the theoretical determination of the electron electric dipole moment (EDM) enhancement factor in this ion and, correspondingly, in gadolinium-containing garnets for which such measurements were recently proposed. Our new value for the EDM enhancement factor of Gd+3 is -2.2 +- 0.5. Calculations of energy levels and lifetimes for Eu~III are used to control the accuracy.Comment: Submitted to Phys. Rev. A 6 pages, 0 figures, 3 table

Oscillator strength, transition rates and lifetimes for n=3 states in Al-like ions

Transition rates, oscillator strengths, and line strengths are calculated for the 3220 possible electric-dipole (E1) transitions between the 73 even-parity 3s3p sup 2 , 3s sup 2 3d, 3p sup 2 3d, 3d sup 2 3s and 3d sup 3 states and the 75 odd-parity 3s sup 2 3p, 3p sup 3 , 3s3p3d, and 3d sup 2 3p states in Al-like ions with the nuclear charges ranging from Z=15 to 100. Relativistic many-body perturbation theory (MBPT), including the Breit interaction, is used to evaluate retarded E1 matrix elements in length and velocity forms. The calculations start from a 1s sup 2 2s sup 2 2p sup 6 Dirac-Fock potential. First-order MBPT is used to obtain intermediate coupling coefficients and second-order MBPT is used to calculate transition matrix elements. Contributions from negative-energy states are included in the second order E1 matrix elements to ensure gauge-independence of transition amplitudes. The transition energies used in the calculation of oscillator strengths and transition rates are from second-order MBPT. Transition rates, line strengths, and oscillator strengths are compared with critically evaluated experimental values and with results from other recent calculations. As a result, we present data for the selected transition, that includes transitions between the 10 even-parity 3s3p sup 2 , 3s sup 2 3p states and the 29 odd-parity 3s sup 2 3p, 3p sup 3 , and 3s3p3d states in Al-like ions. Trends of the transition rates as functions of Z are illustrates graphically for the 220 transitions. Lifetimes of the 10 possible even-parity lower levels and the 27 possible odd-parity upper levels are given for Z=15-100

Sputtering of amorphous silicon nitride irradiated with energetic C60 ions: Preferential sputtering and synergy effect between electronic and collisional sputtering

Amorphous silicon nitride films (thickness 30 nm) deposited on Si(001) were irradiated with 30–1080 keV C60 and 100 MeV Xe ions to fluences ranging from 2 x 10[11] to 1 x 10[14] ions/cm[2]. The composition depth profiles of the irradiated samples were measured using high-resolution Rutherford backscattering spectrometry. The sputtering yields were estimated from the derived composition profiles. Pronounced preferential sputtering of nitrogen was observed in the electronic energy loss regime. In addition, a large synergy effect between the electronic and collisional sputtering was also observed. The sputtering yields were calculated using the unified thermal spike model to understand the observed results. Although the calculated results reproduced the observed total sputtering yields with a lowered sublimation energy, the observed preferential sputtering of nitrogen could not be explained. The present results suggest an additional sputtering mechanism related to the electronic energy loss

Autoionization of Nq+ (q=1-3) Rydberg states produced in high-energy collisions with He

Energy spectra of electrons ejected through autoionization decay of high-Rydberg states in high-energy collisions of Nq+ (q = 1-3) with He have been measured with high resolution by using zero-degree electron spectroscopy. Several series of autoionizing lines were observed, corresponding to decays from N3+ 1s22p(2P)nl Rydberg states produced in N3+ + He collisions, from N2+ 1s22s2p(3P)nl Rydberg states produced in N2+ + He, and from N+ 1s22s2p2(4P)nl Rydberg states produced in N+ + He, respectively. Angular momentum distributions for the first or second peak of three series of C-K electron transitions for Nq+ (q = 1-3) projectiles are also discussed, where the highly excited states are formed by electron excitation

transition rates, and oscillator strengths for n

Relativistic many-body calculations of electric-dipole lifetimes