| State-of-the-art quantum mechanical calculation is a powerful research tool that has been widely used in exploring chemical problems. In this thesis, quantum chemistry is applied to several questions related to semiconductor surface reactions and biofuels. Hybrid organic-Si (001) surface materials have potential industrial applications, especially in molecular electronics. The detailed surface chemistry must be more fully understood to exploit these potential applications. Three systems are discussed: a family of multifunctional molecules that bind in several different ways on Si (001); a previously unstudied surface reaction that may be useful for attaching molecular lines to the surface; and an organic molecule that has been observed to display some unusual dynamic behavior. In each case, a combination of quantum chemical calculations and scanning tunneling microscope (STM) simulation are used to compare to experiments, and new STM methodology is proposed that should allow increased contrast between molecular species on the surface. The work on biofuels described in this thesis is motivated by the search for sustainable energy sources that can replace fossil energy. We applied quantum chemistry understand the reaction mechanism of the dehydration process of D-fructose to HMF. The side reactions of this process have been also studied to understand the low selectivity of this dehydration process. |
