Theoretical model of the interaction of glycine with hydrogenated amorphous carbon (HAC).

摘要: A theoretical model of hydrogenated amorphous carbon (HAC) is developed and applied to study the interaction glycine with HAC surfaces at astronomical temperatures. Two models different H content are tried for surface. The theory Density Functional Theory (DFT) level, including a semiempirical dispersion correlation potential, d-DFT or Grimme DFT-D2. level tested on adsorption Si(001) Crystalline also studied in its two stable phases, α β, metastable γ phase. For Si surfaces, molecular introduced neutral zwitterionic forms, most configurations searched. All predictions checked against experimental observations. films prepared by plasma enhanced vapor deposition room temperature. Glycine deposited 20 K into high vacuum, cold temperature chamber, simulate conditions. Adsorption takes place through acidic group COO(-) when several molecules present, they form H-bond chains among them. Comparison between experiments suggests that possible way improve would require introduction aliphatic polycyclic aromatic core. lack previous amino-acids provides motivation this work.