The objective of this proposal is to identify the chemical mechanism responsible for the mass-independent fractionation of sulfur isotopes seen in Archean sedimentary rocks. We propose to measure the following: 1) high-resolution photoexcitation cross sections of xSO2 ('x' indicates a sulfur isotope, either 32, 33, 34 or 36); 2) the dissociation probabilities for xSO2 from high resolution linewidth and fluorescence measurements; 3)the rates of collisional and radiative deactivation of excited-state xSO2 using fluorescence measurements; 4) the absorption cross sections of xSO; 5) the absorption cross sections for the sulfur isotopologues of CS2. The results of these measurements will be incorporated into photochemical model simulations of sulfur isotopes in the Archean atmosphere.
|Effective start/end date||8/17/15 → 8/16/19|
- NASA: Goddard Space Flight Center: $404,904.00