A comparative theoretical study of the electronic structure of some nickel(II) azides, thiocyanates, and isothiocyanates

1998 ◽  
Vol 76 (7) ◽  
pp. 1006-1014 ◽  
Author(s):  
R H Abu-Eittah ◽  
M El-Esawy ◽  
N Ghoneim ◽  
A T Aly

The electronic structure, conformation, and molecular orbitals of some nickel(II) azides, thiocyanates, and isothiocyanates have been studied. Three different basis sets: split valence (SV), split valence with six d-Gaussians (SV6D), and double zeta (DZ) sets, were used to find the best ground state for nickel. It has been found that the combination, DZ-3F, gives results closest to the experimental values. The electronic structures of the nickel azides studied were completely different from those of the nickel thiocyanates. On the other hand, the electronic structures of the nickel thiocyanates studied were highly comparable to those of the corresponding nickel isothiocyanates. Molecular orbitals were computed for the complexes studied and the types of electronic transitions expected were identified and discussed.Key words: Ni(II) azides, thiocyanates, and isothiocyanates: ab initio SCF calculations; MO calculations on some Ni(II) complexes; theoretical treatment of some Ni(II) ions and salts; geometry and energetics of some nickel(II) azides, thiocyanates, and isothiocyanates.

2009 ◽  
Vol 79-82 ◽  
pp. 1333-1336 ◽  
Author(s):  
Shou Gang Chen ◽  
Wei Wei Sun ◽  
Shuai Qin Yu ◽  
Xun Jun Yin ◽  
Yan Sheng Yin

Theoretical study on the electronic structure of small FemAln(m+n=6) clusters has been carried out at the BPW91 level, and the electronic structures, binding energy and vertical ionization potential of clusters were evaluated. For the stable clusters, the iron atoms gather together and form a maximum of Fe-Fe bonds, and the aluminum atoms locate around Fe core with a maximum of Fe-Al bonds. The binding energy and vertical ionization potential show that the Fe5Al, Fe4Al2 and Fe3Al3 clusters have higher stability, which results provide insight into the properties of iron-aluminides can be obtained from a finite size cluster model.


2001 ◽  
Vol 08 (03n04) ◽  
pp. 281-290 ◽  
Author(s):  
SILVINA ZAPATA ◽  
NORBERTO J. CASTELLANI

The adsorption of monoatomic H on Ni(111) was studied theoretically, taking into account the possibility of H diffusion and eventual incorporation of H as an interstitial. The desorption of H 2 as a diffusion-controlled process from the bulk and the influence on adsorption properties due to a H sub-surface phase very near to the adsorbed phase were considered. Our semiempirical molecular orbital approach allows us to analyze the results from an electronic structure perspective, showing that in general the H–Ni bond is weakened by the presence of the H sublayer.


1981 ◽  
Vol 59 (22) ◽  
pp. 3200-3203 ◽  
Author(s):  
John D. Goddard

The geometries of the S0 and T1 states of thioformaldehyde are determined by ab initio SCF calculations with Gaussian basis sets ranging from minimal to double ζ plus both diffuse and polarization functions. The ground state geometries are all in reasonable agreement with experiment but for the n → π* triplet state split valence or double ζ basis sets yield unreasonably long CS bond distances.


1977 ◽  
Vol 55 (9) ◽  
pp. 1498-1510 ◽  
Author(s):  
Arvi Rauk ◽  
Paul F. Alewood

The thermal and photochemical decomposition of formyl azide in the Curtius rearrangement has been studied by means of RHF–LCAO–MO–SCF calculations augmented by CI. The lower electronic states of carbonyl azides, carbonyl nitrenes, isocyanates, cyanates, oxazirenes, nitrile oxides (fulminates), and isofulminates are discussed on the basis of the results for formyl azide and the corresponding isomers of formula CHNO. The discovery of two nearly degenerate states of A′′ symmetry for formyl azide which may channel decomposition products directly to both isocyanates and carbonyl nitrenes explains some puzzling features of the photolytic Curtius rearrangement. The interconvertibility of the CHNO isomers (and the RCNO isomers) is discussed in terms of the energetics and intended correlations of the accessible electronic states of these species.


2003 ◽  
Vol 631 (1-3) ◽  
pp. 93-99 ◽  
Author(s):  
O Treu Filho ◽  
J.C Pinheiro ◽  
R.T Kondo ◽  
R.F.C Marques ◽  
C.O Paiva-Santos ◽  
...  

2014 ◽  
Vol 665 ◽  
pp. 124-127 ◽  
Author(s):  
Qi Xin Wan ◽  
Bi Lin Shao ◽  
Zhi Hua Xiong ◽  
Dong Mei Li ◽  
Guo Dong Liu

The first-principles with pseudopotentials method based on the density functional theory was applied to calculate the formation energy of impurities and the electronic structure of ZnO doped with Na. In Na-doped ZnO, NaOis the most unstable than the other cases. Simultaneously, NaZnis more stable than Naiaccording to that NaZnhave smaller formation energy. Furthermore, the electronic structure of Na-doped ZnO indicates that that NaZnbehaves as an acceptor, while Naibehaves as a donor.


Author(s):  
Nguyen Van Ha ◽  
Nguyen Thi Thu Hang

Electronic structures of a series of three homodinuclear platinum(II), palladium(II) and gold(I) complexes featuring Janus-type benzoxazolin-2-ylidene bridges and N,N-diisopropyl benzimidazolin-2-ylidene auxiliary ligands have been investigated. The gas-phase molecular structures of all compounds were first optimized using B3PW91 functional and SDD/6-31G(d) combination of basis sets. The nature of their frontier orbitals were then examined. The higher energy occupied molecular orbitals are predominantly d orbital of the metal in combination with p orbital of N,N-diisopropyl benzimidazolin-2-ylidene. On the other hand, the lower energy unoccupied molecular orbitals are p orbitals of the benzoxazolin-2-ylidene. TD-DFT calculations reveal that all the complexes require high energy ultraviolet photon for excitation and photoexcitations form excited state with decreased electron density on metal centers.


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