Relativistic many-body calculations of multipole (E1, M1, E2, M2) transition properties in Al II

TL;DR

This paper provides comprehensive relativistic many-body calculations of multipole transition properties for Al II, significantly expanding the spectroscopic data with high accuracy and reporting many previously unreported lines.

Contribution

The study introduces a combined CI+MBPT method to calculate detailed multipole transition data for Al II, including over 400 transitions across 103 energy levels, with high agreement to experimental data.

Findings

Calculated transition wavelengths and probabilities with ~1% accuracy.

Reported over 80% of transitions as previously unreported.

Expanded the spectroscopic database for Al II significantly.

Abstract

We present systematic relativistic many-body calculations of multipole transition properties for singly charged aluminum ion (Al II) using a method that combines the configuration interaction and many-body perturbation theory (CI+MBPT). Our calculations cover the 103 lowest energy levels in Al II. For five key low-lying configurations (3s2 1S0, 3s3p 3P0, 3s3p 3P1, 3s3p 3P2, 3s3p 1P1), we tabulate the transition wavelengths, reduced matrix elements, transition probabilities, and oscillator strengths for about 400 electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), and magnetic quadrupole (M2) transitions arising from these levels. Our calculated values agree well with available experimental data and other high-precision theoretical calculations, with typical deviations on the order of 1%. Notably, we report over 80% of these transition lines as previously unreported, significantly expanding the existing spectroscopic database for Al II. These results can serve as a valuable reference resource for ongoing precision quantum metrology as well as astrophysical spectroscopy involving Al II ion.