Regular Article

Vibrationally-resolved excitation and dissociation collision strengths of AlO⁺ by electron-impact using the R-matrix method

¹ SGTB Khalsa College, Department of Physics, University of Delhi, Delhi 110007, India
² Department of Physics and Astrophysics, University of Delhi, Delhi 110007, India
³ Keshav Mahavidyalaya, Department of Physics, University of Delhi, Delhi 110 034, India
⁴ Bhaskaracharya College of Applied Sciences, Department of Physics, University of Delhi, New Delhi 110075, India

^a e-mail: sk_savinder2005@yahoo.co.in
^b e-mail: kl_baluja@yahoo.com
^c e-mail: jasmeet.singh@keshav.du.ac.in
^d e-mail: anand_bharadvaja@yahoo.com

Received: 22 October 2018
Received in final form: 23 January 2019
Published online: 4 July 2019

Abstract

The electron-impact calculations are reported for excitation and dissociation of AlO⁺ ion using the R-matrix method. Calculations are performed in the static-exchange (SE) and close-coupling (CC) approximation. Each target state in CC approximation is represented by a configuration interaction (CI) wavefunction that takes into account the correlation and polarisation effects. In CC approximation 14-target states are included in the trial wavefunction of the entire scattering system. Potential energy curves (PECs) for the first four low-lying states are generated using the basis functions 6-311G^* wherein we obtain X¹Σ⁺ as the ground state contrary to a³Π as stated elsewhere in literature. Scattering calculations are then performed to yield vibrationally-resolved electronic excitation collision strengths to the first three lowest excited states a³Π, A¹Π and b³Σ⁺. Using more accurate PECs we calculated the Franck–Condon factors which were then employed to get the vibrationally-resolved electronic excitations and dissociation collision strengths for the fragment channel Al⁺+O of the lowest three excited states a³Π, A¹Π and b³Σ⁺. All scattering calculations are performed at the experimental bond length 1.6178 Å of AlO⁺. Rotational excitation cross sections (0→j, j = 1, 2 … 5) have also been calculated and the corresponding rate coefficients have been evaluated for excitation and de-excitation by using the Maxwellian distribution function for electron temperature upto 5000 K. There are many Feshbach resonances detected in this work. We have analysed only the low-lying resonances below the excitation threshold of A¹Π excited state. Beyond this threshold the resonance structure is too complex to analyse due to many overlapping resonances.