Radiative data in the Zr I spectrum obtained by laser induced fluorescence

Abstract

ABSTRACT Radiative lifetimes of 17 excited states in Zr I, in the energy interval 29000 – 40974 cm -1 , have been investigated using the Time-Resolved Laser-Induced Fluorescence (TR-LIF) method. The levels belong to the 4d 2 5s5p, 4d 3 5p and 4d5s 2 5p electronic configurations were excited in a single - step process from levels belonging to the ground 4p 2 5s a 3 F or to low-lying 4p 2 5s a 3 P, a 5 F terms. For 14 levels, the lifetimes have been measured for the first time. Experimental results are compared with theoretical calculations performed with a multiconfigurational relativistic Hartree–Fock method including core polarization effects.Keywords: Zirconium atom, radiative lifetimes, transition probabilities, time-resolved spectroscopy 1. INTRODUCTION With the extraordinary technological development of laser sources and detectors during the past twenty years, the analytical possibilities of the Laser Induced Fluorescence (LIF ) technique and of the laser-induced spark discharges have become more obvious. Particularly, those techniques have demonstrated their possibilities as efficient tools for the determination of atomic and ionic radiative lifetimes and transition probabilities. The most common laser methods for obtaining radiative lifetimes and transition probabilities are the Time-Resolved Laser-Induced Fluorescence (TR-LIF) technique and the Laser-Induced Breakdown Spectroscopy (LIBS) approach, respectively. In the present work, we apply the TR-LIF method for radiative lifetime measurements of high-lying levels of Zr I. Accurate values of radiative lifetimes and oscillator strengths for spectral lines of neutral zirconium are needed in astrophysics for the determination of the chemical compos ition of solar and, more generally, stellar atmospheres. In a series of previously published papers