Eur. Phys. J. D (2013) 67: 196
https://doi.org/10.1140/epjd/e2013-40310-4

Regular Article

Experimental investigation of photoionization cross section for the 3d ²D excited states of lithium and sodium

¹ National Institute of Lasers and Optronics (NILOP), P.O. Box Nilore, Islamabad 45650, Pakistan
² Department of Physics, International Islamic University, Sector H-10, Islamabad 44000, Pakistan

^a e-mail: dralinadeem@yahoo.com
^b e-mail: shaista.shahzada@iiu.edu.pk

Received: 18 May 2013
Received in final form: 13 June 2013
Published online: 25 September 2013

Abstract

We report experimentally measured photoionization cross sections for the 3d ²D excited states of lithium and sodium at first ionization threshold. The experiments were performed using two dye lasers simultaneously pumped by the second harmonic of a Nd:YAG laser. The vapor contentment and the detection system was a thermionic diode ion detector operating in a space charge limited mode. Photoionization cross sections of the excited states were deduced from the dependence of ion signal intensity on the ionizing laser energies as 19 ± 3 Mb and 21.5 ± 3.5 Mb for lithium and sodium respectively, which are in good agreement with the previously computed theoretical results.