6 research outputs found
Stark Broadening of in III Lines in Astrophysical and Laboratory Plasma
Besides the need of Stark broadening parameters for a number of problems in
physics, and plasma technology, in hot star atmospheres the conditions exist
where Stark widths are comparable and even larger than the thermal Doppler
widths. Using the semiclassical perturbation method we investigated here the
influence of collisions with charged particles for In III spectral lines. We
determined a number of Stark broadening parameters important for the
investigation of plasmas in the atmospheres of A-type stars and white dwarfs.
Also, we have compared the obtained results with existing experimental data.
The results will be included in the STARK-B database, the Virtual Atomic and
Molecular Data Center and the Serbian Virtual Observatory
Atomic data and electron-impact broadening effect in DO white dwarf atmospheres: Si VI
Energy levels, electric dipole transition probabilities and oscillator
strengths in five times ionized silicon have been calculated in intermediate
coupling. The present calculations were carried out with the general purpose
atomic-structure program SUPERSTRUCTURE. The relativistic corrections to the
non-relativistic Hamiltonian are taken into account through the Breit-Pauli
approximation. We have also introduced a semi-empirical correction (TEC) for
the calculation of the energy-levels. These atomic data are used to provide
semiclassical electron-, proton- and ionized helium- impact line widths and
shifts for 15 Si VI muliplet. Calculated results have been used to consider the
influence of Stark broadening for DO white dwarf atmospheric conditions.Comment: MNRAS, accepted, 14 page
Theoretical determination of lifetimes of metastable states in Sc III and Y III
Lifetimes of the first two metastable states in Sc^{2+} and Y^{2+} are
determined using the relativistic coupled-cluster theory. There is a
considerable interest in studying the electron correlation effects in these
ions as though their electronic configurations are similar to the neutral
alkali atoms, their structures are very different from the latter. We have made
a comparative study of the correlation trends between the above doubly ionized
systems with their corresponding neutral and singly ionized iso-electronic
systems. The lifetimes of the excited states of these ions are very important
in the field of astrophysics, especially for the study of post-main sequence
evolution of the cool giant stars.Comment: 13 pages, 1 figure and 5 table