  We use density functional theory (DFT) to investigate the geometric and
electronic structures of multiple 5CB molecules. There are three parts for this
research, test of the arrangement property of the 5CB molecule, calculation of
two 4-n-pentyl-4-cyanobiphenyl (5CB), and four molecules 5CB structure
arrangement. First part reveals the result, which the two 5CBs pointing in
opposite directions case possesses lower total energy, that has the same result
of the optimized caused by the nematic property of 5CBs. In the result of two
5CBs calculation, two 5CBs optimized structures always appears at least one
pair of parallel plains formed by the head benzene of one 5CB and the carbon
chain. In the four 5CBs optimized structure case, we can find out several pairs
of parallel plains consist of benzene plains and one parallel plain in two
carbon chain.
