Computational study of 5d transition metal mononitrides and monoborides using density functional method

Abstract

5d-metal mononitrides and monoborides viz. X-N and X-B (X = La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg) are studied using density functional method based B3LYP functional with LANL2DZ and SDD basis set. The lowest spin state, electron affinities, ionization potentials and binding energies for mononitrides and monoborides are obtained. The electronic state and electronic configuration of mononitrides and monoborides are discussed. Orbitals involved in bond formation are identified. The properties of mononitrides and monoborides are compared. It is found that 5d-metal atoms form stronger bond with nitrogen atom than the boron atom. The range of binding energy, electron affinity and ionization potential is wider for mononitrides than that for monoborides. The properties of 5d-metal mononitrides and 3d-metal mononitrides are also compared. The binding energies for the former are lower than those for the latter.

Computational materials discovery: the case of the W–B system

“…The difference is also obvious, as all the B lines are parallel to each other in oC8-WB, while this pattern is interrupted by one perpendicular B chain between each pair of parallel B lines in tI16-WB (Lundstrom, 1985). Kalamse et al (2010) studied the atomic charges from Mulliken and natural orbital population analysis for 5d transition metal mononitrides and monoborides. They found that W can accept one electron from a B atom to half-fill the 5d orbital, and the bonding characteristic in 5d metal monoborides is of a covalent ionic character with dominant covalent characteristics, as B has a +1 oxidation state.…”

Electronic transitions of platinum monoboride

“…For the upper state of our observed transitions, due to the situation that there is large spin-orbit mixing of the excited states in PtB, the electronic state are only labeled by their value. It is a difficult task to work out the electronic configurations of upper states giving rise to the observed = 1/2 and 3/2 states; however, a simple consideration of promoting one electron from the ground configuration to various higher energy MOs gives many configurations that could be responsible for the = 1/2 and 3/2 states as indicated in configurations (4), (5), and (7).…”

“…Kalamse et al 7 using density functional method based B3LYP functional with LANL2DZ and SDD basis set calculations predicted the ground state bond length and vibrational frequency of PtB to be 906 cm −1 and 1.809 Å, respectively. The vibrational separation is in good agreement with our determined value of 903.6 cm −1 , but the bond length is very different from our 1.741 Å.…”

Структурные, упругие, электронные свойства и межатомные взаимодействия серии металлических тетраборидов MB-=SUB=-4-=/SUB=- (M=Ru, Rh, Pd, Os, Ir, Pt), полученные из FLAPW-GGA-расчетов

“…Следует отметить, что, несмотря на существенные усилия экспериментаторов, была успешно изготовлена только ограниченная группа боридов тяжелых 4d-, 5d-металлов. С теоретической точки зрения к сегодняшнему дню проведен широкий набор расчетов для прогнозирования свойств этих боридов, но большинство из них были посвящены моноборидам [11][12][13][14][15] или диборидам [16][17][18][19][20][21][22][23] тяжелых переходных металлов. Гораздо меньше информации имеется о вышеупомянутых тетраборидах MB 4 .…”