ABSTRACT
Vibronic optical emissions from CS(A1pi --> X1sigma+) and CS(a3pi --> X1sigma+) transitions have been identified from dissociative recombination (DR) of CS2(+) and HCS2(+) plasmas. All of the spectra were taken in flowing afterglow plasmas using an optical monochromator in the UV-visible wavelength region of 180-800 nm. For the CS(A --> X) and CS(a --> X) emissions, the relative vibrational distributions have been calculated for v' < 5 and v' < 3 in both types of plasmas for the CS(A) and CS(a) states, respectively. Both recombining plasmas show a population inversion from the v' = 0 to v' = 1 level of the CS(A) state, similar to other observations of the CS(A) state populations, which were generated using two other energetic processes. The possibility of spectroscopic cascading is addressed, such that transitions from upper level electronic states into the CS(A) and CS(a) states would affect the relative vibrational distribution, and there is no spectroscopic evidence supporting the cascading effect. Additionally, excited-state transitions from neutral sulfur (S(5S(2)0 --> 3P(2)) and S(5S(2)0 --> 3P(1))) and the products of ion-molecule reactions (CS(B1sigma+ --> A1pi), CS(+)(B2sigma+ --> A2pi(i)), and CS2(+) (A2pi(u) --> X2pi(g))) have been observed and are discussed.
ABSTRACT
EPR spectra of semi-met forms of octameric hemerythrin from Themiste zostericola, prepared by one electron reduction of methemerythrin or by one electron oxidation of deoxyhemerythrin, have been visualized at liquid helium temperatures. The spectrum of that prepared by one electron reduction has principal g-values of 1.96 +/- 0.01, 1.88 +/- 0.01, and 1.67 +/- 0.02 while that obtained by one electron oxidation has g = 1.95 +/- 0.01, 1.72 +/- 0.01, and 1.68 +/- 0.02. The amplitude of either spectrum decreases with time on incubation at room temperature according to a first order rate with t 1/2 = 5-8 min, apparently because of an intramolecular disproportionation. Similar EPR spectra have been obtained with semi-metmyohemerythrin of T. zostericola and with the octameric semi-met form of Phascolopsis gouldii. However, these forms disproportionate to a much lesser degree. The azide adduct of the octameric semi-met form of T. zostericola has g-values of 1.94 +/- 0.01, 1.85 +/- 0.01, and 1.57 +/- 0.02. Its EPR spectrum differs somewhat from those of the azide adducts of the octamer of P. gouldii and the monomer of T. zostericola although all are resistant to disproportionation. Methemerythrin and deoxyhemerythrin have no EPR spectra even at liquid helium temperature.
