Photoabsorption and photoionization cross sections are reported from 3d24s4p
, 3d24s4p
and 3d34p
initial states of titanium, reaching final-state energies from −500 to 8000 cm−1 relative to the first ionization threshold 3d24s4F3/2. The nearly ab initio calculations use the eigenchannel R-matrix method, the multichannel quantum-defect theory, and the LS → jj relativistic recoupling frame transformation. The last two steps use experimental energies of Ti+ levels. Radial orbitals needed to calculate short-range interaction parameters are obtained in a multiconfiguration Hartree–Fock approximation that directly generates natural orbitals for the target states. This method bypasses an intermediate step followed in earlier eigenchannel R-matrix studies, in which a set of primitive orbitals was used. Theoretical cross sections are compared with experimental data, in particular near the two lowest ionization thresholds 3d24s4F and 3d3 4F. Our results, which at these energies are accurate to within errors of ∼0.03 in the quantum defects, account for most of the experimental features. Predictions are also made for the spectra at higher energies, where overlapping Rydberg series seriously complicate the photoabsorption pattern.
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Ionization limit, 55 072.5 cm−1.10 The effective quantum numbers are calculated relative to 3d24s4F and 3d24s2F Ti+ states for 3Do and 3Go and relative to 3d3 4F for 5Fo. We also tabulate a few dominant components and their weights in the CI expansion sets.
Ref. 10.
Table 4
Theoretical and Experimental Energies (cm−1) and Effective Quantum Numbers of 3d24s(4F7/2)∊d Autoionizing Series in the Photoionization Cross Section of the 3d24s4p Level
ν are effective quantum numbers associated with Ti+ states.
Short-range perturber.
Two overlapping 3F3 and 3D3 levels.
Three overlapping 3G5, 3H5, and 3I5 levels.
Two overlapping, but distinct, 3d24s(2D)6d3F3 and 3d3(2D)5s3D3 levels.
Tables (5)
Table 1
Theoretical and Experimental Term-Average Energies (cm−1) of Even-Parity Ti+ States Relative to the Ground Level 3d24s4F3/2
Ionization limit, 55 072.5 cm−1.10 The effective quantum numbers are calculated relative to 3d24s4F and 3d24s2F Ti+ states for 3Do and 3Go and relative to 3d3 4F for 5Fo. We also tabulate a few dominant components and their weights in the CI expansion sets.
Ref. 10.
Table 4
Theoretical and Experimental Energies (cm−1) and Effective Quantum Numbers of 3d24s(4F7/2)∊d Autoionizing Series in the Photoionization Cross Section of the 3d24s4p Level
ν are effective quantum numbers associated with Ti+ states.
Short-range perturber.
Two overlapping 3F3 and 3D3 levels.
Three overlapping 3G5, 3H5, and 3I5 levels.
Two overlapping, but distinct, 3d24s(2D)6d3F3 and 3d3(2D)5s3D3 levels.
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