Showing papers by "Rajendra R. Zope published in 2009"

Boron fullerenes: From B 80 to hole doped boron sheets

Abstract: We demonstrate the existence of a family of stable boron fullerenes containing $80{n}^{2}$ atoms that is related to the family of $60{n}^{2}$ carbon icosahedral fullerene series and is compatible with the recently proposed stable boron sheets composed of triangular and hexagonal motifs. All electron density-functional calculations on the ${\text{B}}_{320}$, ${\text{B}}_{720}$, ${\text{B}}_{1280}$, and ${\text{B}}_{2000}$ confirm their stability and show that the quantum size effects open up electronic band gaps in the boron fullerenes at ${\text{B}}_{1280}$. Boron fullerenes below ${\text{B}}_{2000}$ have valence electronic structure identical to their corresponding carbon cousins from $60{n}^{2}$ family.

The α-boron cages with four-member rings

Abstract: A new class of 32n2 boron cages which are made closed by six squares is proposed and a procedure to build such cages using an α-boron sheet is described. Each member from this infinite set of boron cages has a structure that is compatible with the most stable α-boron sheet that maintains an optimal balance of the two-center and three-center bonds. Accurate density functional calculations with a large polarized Gaussian basis set show that B32, B96, B128, and B288 are energetically stable structures. The smallest B32 cage from this class has the HOMO-LUMO gap of 1.32 eV, the largest amongst the boron cages and boron fullerenes studied so far.

Dipole polarizability of isovalent carbon and boron cages and fullerenes

Abstract: Recent works have shown that the nonmetallic $\ensuremath{\alpha}$-boron cages and fullerenes have valence electronic structures that are identical to those of the corresponding carbon cages and fullerenes to which they are structurally related. By studying the first-order response of these systems (${\text{C}}_{60}$, ${\text{B}}_{80}$, ${\text{C}}_{240}$, and ${\text{B}}_{320}$ fullerenes and ${\text{C}}_{24}$ and ${\text{B}}_{32}$ cages) to an applied static electric field, we show that this similarity in valence electron structures results in an interesting relation between their dipole polarizabilities. The dipole polarizabilities of the $\ensuremath{\alpha}$-boron cages and fullerenes obtained by density functional calculations are simply proportional to the dipole polarizabilities of the related carbon cages and fullerenes.