Molecular orbital calculations for dialuminum and disilicon hydrides and related systems

1985 ◽  
Vol 63 (1) ◽  
pp. 71-76 ◽  
Author(s):  
N. Colin Baird
Keyword(s):  
Molecular Orbital ◽  
Electron Correlation ◽  
Surface Structures ◽  
Molecular Orbital Calculations ◽  
Mo Calculations ◽  
Mndo Calculations ◽  
Derivatives Of

Abinitio MO calculations for Si2H2 are reviewed and discussed in qualitative terms. New calculations are reported, by MNDO for Si2H2 and Si2H4, and using both MNDO and abinitio methods (including electron correlation at the MP2 level) for various possible structures for Al2H2 (3). As with the analogous silicon dihydride, a dibridged structure 3a is found to be superior to classical structures 3b, 3c, and 3d. MNDO calculations for derivatives of Al2H2 are reported. Finally, some implications of the calculations for the surface structures of partially-hydrogenated elemental aluminum and silicon are discussed.

Synthesis, Optical Properties, Structures and Molecular Orbital Calculations of Subazaporphyrins, Subphthalocyanines, Subnaphthalocyanines and Related Compounds

1999 ◽  
Vol 03 (06) ◽  
pp. 453-467 ◽  
Author(s):  
NAGAO KOBAYASHI
Keyword(s):  
Molecular Orbital ◽  
Magnetic Circular Dichroism ◽  
Soret Band ◽  
Ring Expansion ◽  
Molecular Orbital Calculations ◽  
Mo Calculations ◽  
Key Points ◽  
Adsorption Data ◽  
Ring Expansion Reaction ◽  
Related Compounds

The synthesis of and spectroscopic data on subazaporphyrins, subphthalocyanines, subnaphthalocyanines and their related compounds reported to date are summarized, together with the results of molecular orbital (MO) calculations from our laboratory. Thus the problems and key points in the synthesis of these subazamacrocycles and their electronic absorption and magnetic circular dichroism (MCD) spectra are discussed, together with those of the monosubstituted-type low-symmetrical phthalocyanines obtained by their ring expansion reaction. The Q bands of these subazamacrocycles are orbitally doubly degenerate, and in the Soret band region, three transitions to the orbitally degenerate state are found. The MO calculations suggest that the HOMO levels destabilize considerably while the LUMO levels change slightly with increasing size of the π system. In addition, the electronic adsorption data are reproduced by the calculation only when the two pyrrole hydrogens in the monosubstituted-type phthalocyanines are assumed to be linked to the two pyrrole nitrogens along the short axis.

MNDO calculations for some allotropes, hydrides, and oxides of phosphorus

1984 ◽  
Vol 62 (2) ◽  
pp. 341-347 ◽  
Author(s):  
N. Colin Baird
Keyword(s):  
Molecular Orbital ◽  
Strain Energy ◽  
Mndo Method ◽  
Molecular Orbital Calculations ◽  
Mndo Calculations

Molecular orbital calculations by the MNDO method are reported for some allotropes, hydrides, and oxides of phosphorus. The aim of the study is to test further the ability of MNDO to reproduce the energetics of PP, PH, and PO bonds, and to apply MNDO to interesting problems in the chemistry of such systems. Different isomers of P4, P6, and P8 are considered, as well as ions of P3, P5, and P7. The method is found to overestimate strain energy in three-membered rings, and to underestimate the strength of three-electron PP bonds. The strength of PO π bonds apparently also is overestimated. Possible isomers of P2O2 and P2O3 are discussed.

Molecular Orbital Calculations on the Interaction of Ni and Cu Atoms with PN

1981 ◽  
Vol 36 (10) ◽  
pp. 1092-1094
Author(s):  
H. Itoh ◽  
G. Ertl
Keyword(s):  
Electron Transfer ◽  
Bond Strength ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Weak Interactions ◽  
Bond Formation ◽  
Molecular Orbital Calculations ◽  
Kcal Mole ◽  
Mo Calculations ◽  
Ab Initio Mo Calculations

Ab initio MO calculations for PN predict a pronounced electron transfer from the P to the N atom. Only very weak interactions result for M-PN (M = Ni, Cu) configurations whereas bond formation is predicted if the N atom couples to the metal. The bond strength for Ni (10.5 kcal/mole) is about twice as large as for the Cu-NP complex (4.6 kcal/mole). Coupling occurs mainly with the 7 σ-level (HOMO) of the ligand whose energy is lowered below that of the 2 π-level.

Reduction of Orbital Space for Molecular Orbital Calculations with Quantum Computation Simulator for Educations

2019 ◽  
Author(s):  
Yuji Mochizuki ◽  
Koji Okuwaki ◽  
Takumi Kato ◽  
Yuichiro Minato
Keyword(s):  
Quantum Computation ◽  
Molecular Orbital ◽  
Preliminary Test ◽  
Molecular Orbital Calculations ◽  
Natural Orbital ◽  
Mo Calculations ◽  
Crucial Issue ◽  
Teaching Materials ◽  
Orbital Space ◽  
The Cost

Recently, the molecular orbital (MO) calculations with quantum computations (QCs) have attracted considerable interest. The cost of QCs highly depends on the number of qubits even on quantum simulators. The reduction of MO space can thus be a crucial issue for the practical applicability of MO-QC. Besides the frozen-core restriction for the occupied MO space, we have used the pseudo-natural orbital derived from the second-order M{\o}ller-Plesset perturbation (MP2) theory for the virtual MO space. A preliminary test on the LiH molecule (STO-3G basis) showed acceleration by a factor larger than 500 for MO-QC with the Blueqat simulator, where the required time was 72 s per solution. Simulations of MO-QC may be used as practical teaching materials in classes.

Mössbauer study and molecular orbital calculations on some bimetallic derivatives of ferrocene and ferricinium

1993 ◽  
Vol 77 (1) ◽  
pp. 51-66 ◽  
Author(s):  
Hamid Rabah ◽  
Jacques Guillin ◽  
Annie Cereze-Ducouret ◽  
Jean-Marc Greneche ◽  
Daniel Talham ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Molecular Orbital Calculations ◽  
Mössbauer Study ◽  
Derivatives Of

The Photoelectron Spectra of the N-Chloro and N-Bromo Derivatives of Dimethylamine

1979 ◽  
Vol 32 (4) ◽  
pp. 719 ◽  
Author(s):  
F Carnovale ◽  
T Gan ◽  
JB Peel
Keyword(s):  
Energy Range ◽  
Molecular Orbital ◽  
Ionization Energy ◽  
Lone Pair ◽  
Photoelectron Spectra ◽  
Molecular Orbital Calculations ◽  
Ionization Energies ◽  
Resonance Effects ◽  
Derivatives Of ◽  
Lone Pair Interactions

The He I and He II spectra obtained for chlorodimethylamine (CH3)2NCl, and bromodimethylamine (CH3)2NBr, complete the study of the N-chloro and N-bromo derivatives of the small amines. The valence photoelectron spectra are interpreted with the aid of SPINDO molecular orbital calculations. Trends in the observed ionization energies for both series of small halo amines are described in terms of variations in inductive and resonance effects, the latter particularly concerning the nN/nx lone-pair interactions observed in the low ionization energy range.

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