EGAS41 - Swansea University

41 st EGAS CP 31 Gdańsk 2009
Large scale CIV3 calculations of fine-structure energy levels
and lifetimes in Al-like Vanadium
G.P. Gupta 1,∗ , A.Z. Msezane 2
1 Department of Physics, S. D. (Postgraduate) College, Muzaffarnagar – 251 001,
(Affiliated to Choudhary Charan Singh University, Meerut – 250 004), INDIA
2 Department of Physics and Center for Theoretical Studies of Physical Systems,
Clark Atlanta University, Atlanta, Georgia 30314, USA
∗ Corresponding author: g p gupta1@yahoo.co.in
We have performed large scale CIV3 calculations of excitation energies from ground states
for 97 fine-structure levels as well as of oscillator strengths and radiative decay rates
for all electric-dipole-allowed and intercombination transitions among the fine-structure
levels of the terms belonging to the (1s 2 2s 2 2p 6 )3s 2 3p, 3s3p 2 , 3s 2 3d, 3p 3 , 3s3p3d, 3p 2 3d,
3s3d 2 , 3p3d 2 , 3s 2 4s, 3s 2 4p, 3s 2 4d, 3s 2 4f, and 3s3p4s configurations of V XI, using very
extensive configuration-interaction (CI) wave functions [1]. The important relativistic
effects in intermediate coupling are incorporated by means of the Breit-Pauli Hamiltonian
which consists of the non-relativistic term plus the one-body mass correction, Darwin
term, and spin-orbit, spin-other-orbit, and spin-spin operators [2]. The errors, which
often occur with sophisticated ab initio atomic structure calculations, are reduced to a
manageable magnitude by adjusting the diagonal elements of the Hamiltonian matrices. In
this calculation we have investigated the effects of electron correlations on our calculated
data, particularly on the intercombination transitions, by including orbitals with up to
n=5 quantum number. We considered up to three electron excitations from the valence
electrons of the basic configurations and included a large number of configurations (1164)
to ensure convergence.
Our adjusted excitation energies, including their ordering, are in excellent agreement
with the recommended data by the National Institute of Standard and Technology (NIST).
In this calculation the mixing among several fine-structure levels is found to be very strong.
Due to this strong mixing sometime it is very difficult to identify these levels correctly.
In our CIV3 calculation we identify the levels by their dominant eigenvector [3, 4]. We
believe that our very extensive calculations may assist the experimentalists in identifying
these strongly mixed levels. From our transition probabilities, we have also calculated
radiative lifetimes of the fine-structure levels in V XI. Significant differences between our
calculated lifetimes and those of Froese Fisher et al. [5] for several fine-structure levels
are discussed. We predict new data for several levels where no other theoretical and/or
experimental results are available.
References
[1] A. Hibbert, Comput. Phys. Commun. 9, 141 (1975)
[2] R. Glass, A. Hibbert, Comput. Phys. Commun. 16, 19 (1978)
[3] G.P. Gupta, K.M. Aggarwal, A.Z. Msezane, Phys. Rev. A 70, 036501 (2004)
[4] K.M. Aggarwal, Vikas Tayal, G.P. Gupta, F.P. Keenan, At. Data Nucl. Data Tables
93, 615 (2007)
[5] Ch. Froese Fisher et al., At. Data Nucl. Data Tables 92, 607 (2006)
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