title: Ab initio calculation of the electronic band structure, density of states and optical properties of alpha-2-methyl-1-nitroisothiourea.
abstract: The electronic and optical properties of alpha-2-methyl-1-nitroisothiourea have been studied using a full potential linear augmented plane wave method within density-functional theory along with the Engel-Vosko exchange correlation function. The structural data obtained by Vasil'ev et al. [Vasil'ev, A. D.; Astakhov, A. M.; Gelemurzina, I. V.; Stepanov, R. S. Dokl. Chem. 2001, 379, (4-6), 232-235; translated from Dokl. Akad. Nauk 2001, 379 (6), 781-784] from X-ray diffraction was used. Our calculations show that the valence band maximum (VBM) is located at the T and the conduction band minimum (CBM) is located at the R point of the Brillouin zone, resulting in an indirect energy gap of 3.1 eV. The calculated partial density of states shows that the upper valence band and the lower conduction band arise predominantly from the O-p, N-p and S-p states. The compound has a large uniaxial dielectric anisotropy and a large negative birefringence.
authors.affiliation: Institute of Physical Biology, South Bohemia University, Nove Hrady 37333, Czech Republic. maalidph@yahoo.co.uk
authors.forename: Ali Hussain
authors.initials: AH
authors.lastname: Reshak
authors.forename: Dalibor
authors.initials: D
authors.lastname: Stys
authors.forename: S
authors.initials: S
authors.lastname: Auluck
authors.forename: I V
authors.initials: IV
authors.lastname: Kityk
mesh_terms: D008958:Models, Molecular; D013890:Thiourea / Q000031:analogs & derivatives* / Q000737:chemistry; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: C544996:alpha-2-methyl-1-nitroisothiourea; D013890:Thiourea