Modeling the Si(100) Surface
The Si surface is the Si surface most frequently used for building electronic devices. An experimental study observed that when a bare Si surface is exposed to H2 at low temperatures, H2 molecules tend to chemisorb next to each other.1 This effect can potentially be used to build long linear nanostructures on the Si surface. They could serve as a bridge between conventional electronic devices and molecular electronics.
I modeled the adsorption of H2 on the Si surface using a plane-wave code VASP at the PW91 level of theory and found that the chemisorption of H2 molecules in orderly rows is indeed more favorable than in random order.
I also modeled H2-induced changes in Si surface topology using VASP at the PW91 level of theory and the GAMESS package at the MRMP2 level of theory.