A vacuum ultraviolet laser photoionization and pulsed field ionization study of nascent S(3P2,1,0) and S(1D2) formed in the 193.3 nm photodissociation of CS2

The photoionization efficiency (PIE) and pulsed field ionization-photoion (PFI-PI) spectra for sulfur atoms S(P-3(2,1,0)) and S(D-1(2)) resulting from the 193.3 nm photodissociation of CS2 have been measured using tunable vacuum ultraviolet (vuv) laser radiation in the frequency range of 82 750-83 570 cm(-1). The PIE spectrum of S(P-3(2,1,0)) near their ionization threshold exhibits steplike structures. On the basis of the velocity-mapped ion-imaging measurements, four strong autoionizing peaks observed in the PIE measurement in this frequency range have been identified to originate from vuv excitation of S(D-1(2)). The PFI-PI measurement reveals over 120 previously unidentified new Rydberg lines. They have been assigned as Rydberg states [3p(3)(S-4 degrees)nd(3)D degrees (n = 17-64)] converging to the ground ionic state S+(S-4) formed by vuv excitations of S(P-3(2,1,0)). The converging limits of these Rydberg series have provided more accurate values, 82 985.43 +/- 0.05, 83 162.94 +/- 0.05, and 83 559.04 +/- 0.05 cm(-1) for the respective ionization energies of S(P-3(0)), S(P-3(1)), and S(P-3(2)) to form S+(S-4). The relative intensities of the PFI-PI bands for S(P-3(0)), S(P-3(1)), and S(P-3(2)) have been used to determine the branching ratios for these fine structure states, S(P-3(0)):S(P-3(1)):S(P-3(2))=1.00:1.54:3.55, produced by photodissociation of CS2 at 193.3 nm. (c) 2008 American Institute of Physics.