We present an overview of a semi-empirical kinetic model of chemical reaction product formation due to simultaneous irradiation of carbon by O+ and H+ symbolically represented by O+-H+→C. The model was developed in conjunction with our experimental studies of the O+-H+→C and the O+-H+→C/B irradiation cases; C/B represents boron-doped graphite. Model predictions were made for flux and energy dependence, and generally good agreement with experimental results has been seen for both single-species cases: H+→C and O+→C. For the O+-H+→C reaction, the model agrees quite well with the flux ratio-dependence of the H2O yield, the resulting CO and CO2 yield reductions, and the CH4 yield reduction.