Ab Initio Studies on Electronic Structure and Charge Density of Potato Starch

Starch is a carbohydrate consisting of a large number of glucose units joined by glycosidic bonds. An ab initio study based on density functional theory implemented in computational program SIESTA is the prime theme of present paper. In which LDA exchange co-relation environment is used to obtain density of states (DOS), projected/partial density of states (PDOS), charge density, electronic band structure of some potato starch. In the first step the structure of Potato starch ( PS), glutaraldehyde (GA) and crosslinked PS-GA systems are optimized for lowest energy value. On the basis of band plot and PDOS, it can be stated that the system under study is electronically insulator but charge density analysis proves it as ionic conductors. Moreover, the contributions to the top of valence band (HOMO) and bottom of conduction band(LUMO) come predominantly from O s/p, C s/p and H s states, respectively. This is a preliminary and first study to observe theoretically the effect of cross-linking of GA in PS before its further application as an electrolyte in various electrochemical devices.