MD studies of the structural and diffusion properties of formamide/water and ethanol/water mixtures on titanium and platinum surfaces

Formamide - surface interaction was one of the main discussion topicsat the round table meeting "Astrobology: New Ideas and ResearchTrends" of the Italia - Russia@Dubna (2011). The nucleic acid componentssynthesized by formamide and their cosmic dust analogs havebeen widely considered to be the best candidates with regards to the earlystages of the formation of biological molecules needed for life. Titaniumdioxide (TiO₂, anatase), zircon (ZrO₂), and other minerals could influence as matrix elements the synthesis of nucleic acid bases from formamide,which is followed by temperature and UV heating. In the darkconditions, the experimental data on formamide adsorption at 300 K overthe (001) plane of TiO₂ indicate some amount of unreacted formamideand water among the products (CO, H₂, NH₃, HCN). So far, some concentrationof water and its involvement in formamide/TiO₂ interactionhas been experimentally shown to be an important component of the process.In this paper, molecular dynamics (MD) simulation of interactionbetween a formamide - water solution and a TiO₂ (anatase) surface isperformed. A comparative MD analysis is done of the formamide -water/(TiO₂, Pt) and ethanol - water/(TiO₂, Pt) systems in a temperaturerange from T = 250 K to T = 400 K to compare their structural anddiffusion properties.