I propose to model a detailed structure of kerogen to be used as input to the molecular simulations. The molecular models of kerogen capture its heterogeneity, functional groups, as well as compositional and structural details as indicated in previously documented experimental data. The model will also consider the effect of kerogen type and maturity on its structure. Finally, the model will account for changes in hydrogen and oxygen content, amount of oxygen containing functional groups, and changes in aromaticity with kerogen of different types and thermal maturity. This task will be used to evaluate objectives I and II and verify hypotheses I and II.