Single- and multiphoton infrared laser spectroscopy of atomic negative ions

Abstract

<p>A pulsed, tunable infrared laser source (0.6-5.2 μm) has been developed on the basis of a commercial dye laser and non-linear optical conversion techniques. This laser source was combined with a keV negative ion beam apparatus in a crossed-beam geometry, with the aim to systematically study several atomic negative ions through a variety of single- and multiphoton detachment experiments. Photodetachment threshold spectra of 21 ionic species (B- , C- , O- , Al- , Si- , Cr- , Co- , Ni- , Cu- , Ge- , Mo- , Rh- , Pd- , Ag- , Sn- , Sb- , Te- , Cs- , Ir- , Pt- , and Bi- ) have been recorded, in most cases resulting in very accurate determinations of ionic binding energies, marking substantial improvements over previous experimental values. In fact, several ionic states investigated here had not been observed previously. Different schemes for resonant multiphoton detachment of atomic negative ions were demonstrated for the first time. These studies were conducted with several anions (Si- , Sri- , Sb- , Te- , Ir- , and Pt- ) providing highly accurate ionic energy level splittings and clearly demonstrating that multiphoton probes are generally applicable to negative ion structure.</p>