DOI: 10.5281/zenodo.18325865
title: R-matrix electron-impact-excitation of Te I - V and photoionization of Te I - IV

description: This database contains calibrated R-matrix electron impact excitation data and photoionization data. 

This database comprises the data published at Mulholland et al (2024) (excitation, Te I - III) as well as Mulholland et al (2026) (excitation Te IV - V, photoionization Te I - IV.

 

The maxwellian averaged electron-impact-excitation data is stored in the standard adf04 format (https://open.adas.ac.uk/adf04) in excitationUpsilon.tar. The header contains information about the ion - namely its atomic symbol, charge and ionization potential. Immediately following this is the level information, in the format 'index, configuration, lsj term, energy.' This is terminated with a -1. Following this are one float, one integer, and the temperature grid (in Kelvin) on which the effective collision strengths are stored. The transition indices, a-values, effective collision strengths and Bethe limit points are then listed row-wise. The Bethe limit points are marked negative for electric-dipole transitions. Transitions are terminated by -1 -1. After a final -1, there is information pertaining to the calculation. For these datasets the input to the atomic structure code grasp0 (Dyall, Grant et al 1989) is included at the bottom of the files. These structures can then be carried forward to the DARC R-matrix codes to reproduce the data. 

In addition, we have attached the raw OMEGA data files, which contain the collision strengths (not yet averaged) as a function of incident electron energy. Their format is described in Table 3 and surrounding text of Fernández-Menchero et al (2020). There are no elastic transitions in the files. Essentially, the format lists the nuclear charge (Z) and number of electrons (N), followed by the number of levels (NAST), number of energy points and number of transitions. The angular quantum numbers then follow in the form (0,2J). The bound-state energies then follow in scaled Rydbergs (Ryd/z^2, where z = min(1, Z-N).) Then, the incident energies (in scaled Rydbergs) and OMEGA values follow. The OMEGA values are ordered by lower level - i.e 1-2, 1-3, ... , 1-NAST, 2-3,2-4,... 2-NAST, etc. The last point in each file is the Bethe limit point, which is only listed for dipole transitions. This is potentially useful for those modellers who wish to use the raw-OMEGA for non-thermal excitation. Note there is a single energy grid in this file - and therefore the lower-level energy must be subtracted from this for each transition to get a true lower -> final energy grid.

 

The photoionization data is formatted as follows. Each transition between ion stages has its own directory. Within each of these are the bound levels calculated by grasp0 (Dyall, Grant et al 1989) for the final state. These are shifted to experimental values, and the LSJ eigenvector calculated from  jj2lsj (Gaigalas et al 2017) is indicated. The R-matrix bound levels calculated by STGB (unpublished, but theory described here) are also shown. These form the initial states for photoionization. Each subdirectory then contains cross-sections for a given initial symmetry (2J,π).  The naming convention of the data files are XPI_{2JP}_B{NUM}.dat, where 2JP is the (doubled) angular momentum and parity, and NUM is the level number within that initial symmetry. The files are formatted with two header lines, firstly:  0, 2J, parity, level number ;  and secondly: the ionization potential (Rydberg) and number of energy points in the file.  The data then follows in the format,

 $$ h\nu, \hspace{5mm} \Sigma_{all} \sigma_{i \to j},\hspace{5mm} \sigma_{i \to 1,2,...,10},\hspace{5mm} \Sigma_{j>10} \sigma_{i \to j} $$,

i.e photon-energy, total-cross-section, 10-partial cross sections, and then the sum of the remaining partial cross sections in the calculation. I.e, the final 11 columns add up to the second. The total cross sections are typically used in modelling - but we have also included partial (level-to-level) cross sections for the first 10 levels of the neighbouring ion for those modellers who require them. 

For inquiries regarding these data sets, contact Leo Patrick Mulholland at lmulholland25@qub.ac.uk.