Collisional- and photo-excitations of Ca IV including strong 3.2 $\mu$m emission line

Abstract

We report a detailed study of features of electron-impact excitation (EIE) of Ca IV for the first time using the relativistic Breit-Pauli R-Matrix method with a large close coupling wavefunction expansion of 54 fine structure levels belonging to n=2,3,4 complexes. Our study predicts presence of a strong 3.2 $\mu$m emission line in IR. The EIE collision strength ($\Omega$) shows extensive resonances with enhanced background resulting in an effective collision strength ($\gamma$) of 2.2 at about 10,000 K that increases to 9.66 around 300,000 K. The present results include collision strength of all 1431 excitations among the 54 levels and effective collision strength for a limited number of transitions of possible interest. We have found extensive resonances in the low energy region, convergence of the resonances, and of the partial waves with the 54 levels wavefunction. At higher energy, the collision strength decreases beyond the resonance region for forbidden transitions, is almost constant or decreases slowly for dipole-allowed transitions with low oscillator strengths, and rises with Bethe-Coulomb behavior of ln(E)to almost a plateau for transitions with high f-values.

References in corpus (5)

• The chemical composition of the Sun
• SN 2019ehk: A Double-Peaked Ca-rich Transient with Luminous X-ray Emission and Shock-Ionized Spectral Features
• Atomic data from the Iron Project. LIII. Relativistic allowed and forbidden transition probabilities for Fe XVII
• Atomic data from the Iron Project XLV. Relativistic transition probabilities for carbon-like Ar XIII and Fe XXI using Breit-Pauli R-matrix method
• New rest wavelength determinations for 7 mid-infrared fine structure lines by ISO-SWS

Cited by in corpus (2)

• Emission lines due to ionizing radiation from a compact object in the remnant of Supernova 1987A
• Nebular spectra from Type Ia supernova explosion models compared to JWST observations of SN 2021aefx