Absolute high-resolution Se+ photoionization cross-section measurements with Rydberg-series analysis

Authors

D. A. Esteves, University of Nevada - Reno
R. C. Bilodeau, Lawrence Berkeley National Laboratory
N. C. Sterling, Michigan State University
R. A. Phaneuf, University of Nevada - RenoFollow
A. L. D. Kilcoyne, Lawrence Berkeley National LaboratoryFollow
E. C. Red, Lawrence Berkeley National Laboratory
A. Aguilar, Lawrence Berkeley National LaboratoryFollow

Date of this Version

2011

Citation

Physical Review A 84, 013406 (2011); DOI: 10.1103/PhysRevA.84.013406

Abstract

Absolute single photoionization cross-section measurements for Se⁺ ions were performed at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory using the photo-ion merged-beams technique. Measurements were made at a photon energy resolution of 5.5 meV from 17.75 to 21.85 eV spanning the 4s²4p³4S^o_3/2 ground-state ionization threshold and the ²P^o_3/2,²P^o_1/2,²D^o_5/2, and²D^o_3/2 metastable state thresholds. Extensive analysis of the complex resonant structure in this region identified numerous Rydberg series of resonances and obtained the Se²⁺ 4s²4p^{2 3}P₂ and 4s²4p^{2 1}S₀ state energies. In addition, particular attention was given to removing significant effects in the measurements due to a small percentage of higher-order undulator radiation.