## Molecular Orbital

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### Xueye Wang - One of the best experts on this subject based on the ideXlab platform.

• ##### Tribochemistry of ZDDP in Molecular Orbital calculations
Tribology International, 2004
Co-Authors: Weijiu Huang, Xueye Wang
Abstract:

The Molecular Orbital parameters of zinc dialkyldithiophosphate (ZDDP) and several metal-atom-cluster models were calculated. The nature and the strength of the interactions between the ZDDP molecules and different metal surfaces are analysed and discussed with the use of frontier Orbital theory. By comparing the highest occupied Molecular Orbital energy (EHOMO) and the lowest unoccupied Molecular Orbital energy (ELUMO) of the ZDDP and the atoms cluster models of Al6, Cu6, and Fe5, it is concluded that ZDDP behaves as an excellent boundary lubricant additive at the interface with iron. The derived Molecular Orbital parameters illustrate the advantages for tribochemistry studies.

• ##### Tribochemistry of ZDDP in Molecular Orbital calculations
Tribology International, 2004
Co-Authors: Yuanqiang Tan, Weijiu Huang, Xueye Wang
Abstract:

The Molecular Orbital parameters of zinc dialkyldithiophosphate (ZDDP) and several metal-atom-cluster models were calculated. The nature and the strength of the interactions between the ZDDP molecules and different metal surfaces are analysed and discussed with the use of frontier Orbital theory. By comparing the highest occupied Molecular Orbital energy (EHOMO) and the lowest unoccupied Molecular Orbital energy (ELUMO) of the ZDDP and the atoms cluster models of Al6, Cu6, and Fe5, it is concluded that ZDDP behaves as an excellent boundary lubricant additive at the interface with iron. The derived Molecular Orbital parameters illustrate the advantages for tribochemistry studies.

• ##### Molecular Orbital indexes criteria for friction modifiers in boundary lubrication
Tribology International, 2002
Co-Authors: Weijiu Huang, Xueye Wang
Abstract:

Abstract Friction modifiers, due to their adsorption onto metal surfaces, play an important role in boundary lubrication. The Molecular Orbital indexes were used as the criteria to study the interaction between lubricant polar end groups and metal surfaces. By comparing the net electric charge of bonding atoms, the highest occupied Molecular Orbital energy (E HOMO ) and the lowest unoccupied Molecular Orbital energy (E LUMO ) of interactive molecules, one could find that the hydrogen bond strength between alcohol and oxide metal surface which is hydroxylated was stronger than that between a hydroxylated oxide metal surface and ester. On the other hand, the interaction between naked aluminium atoms and ester is stronger than that between naked aluminium atoms and alcohol. Thus, lubricants consisting of alcohol and ester show a combination friction-reducing effect because each of the two components has its own advantages in interaction with the hydroxylated aluminium oxide and naked aluminium atoms on the lubricated interface.

### Richard Pincak - One of the best experts on this subject based on the ideXlab platform.

• ##### Energy gap between highest occupied Molecular Orbital and lowest unoccupied Molecular Orbital in multiwalled fullerenes
Physical Review A, 2009
Co-Authors: M. Pudlak, Richard Pincak
Abstract:

We report on the electronic structure of the C60-C240 multiwalled fullerene onion near the Fermi level. The analytical expressions for the hybridizations of the Orbitals on the fullerene shells were derived. The difference between the Fermi levels of individual fullerenes is obtained. The highest occupied Molecular Orbital– lowest unoccupied Molecular Orbital energy gap for the C60-C240 carbon fullerene onion is calculated. The charge transfer from the outer shell to the inner shell in the base state of the onion is determined. Splitting and the shift of the energy levels of the onion as a result of intershell interaction are predicted.

• ##### Energy gap between highest occupied Molecular Orbital and lowest unoccupied Molecular Orbital in multiwalled fullerenes
Physical Review A, 2009
Co-Authors: M. Pudlak, Richard Pincak
Abstract:

We report on the electronic structure of the ${\text{C}}_{60}{\text{-C}}_{240}$ multiwalled fullerene (onion) near the Fermi level. The analytical expressions for the hybridizations of the $\ensuremath{\pi}$ Orbitals on the fullerene shells were derived. The difference between the Fermi levels of individual fullerenes is obtained. The highest occupied Molecular Orbital--lowest unoccupied Molecular Orbital energy gap for the ${\text{C}}_{60}{\text{-C}}_{240}$ carbon fullerene onion is calculated. The charge transfer from the outer shell to the inner shell in the base state of the onion is determined. Splitting and the shift of the energy levels of the onion as a result of intershell interaction are predicted.

### M. Pudlak - One of the best experts on this subject based on the ideXlab platform.

• ##### Energy gap between highest occupied Molecular Orbital and lowest unoccupied Molecular Orbital in multiwalled fullerenes
Physical Review A, 2009
Co-Authors: M. Pudlak, Richard Pincak
Abstract:

We report on the electronic structure of the C60-C240 multiwalled fullerene onion near the Fermi level. The analytical expressions for the hybridizations of the Orbitals on the fullerene shells were derived. The difference between the Fermi levels of individual fullerenes is obtained. The highest occupied Molecular Orbital– lowest unoccupied Molecular Orbital energy gap for the C60-C240 carbon fullerene onion is calculated. The charge transfer from the outer shell to the inner shell in the base state of the onion is determined. Splitting and the shift of the energy levels of the onion as a result of intershell interaction are predicted.

• ##### Energy gap between highest occupied Molecular Orbital and lowest unoccupied Molecular Orbital in multiwalled fullerenes
Physical Review A, 2009
Co-Authors: M. Pudlak, Richard Pincak
Abstract:

We report on the electronic structure of the ${\text{C}}_{60}{\text{-C}}_{240}$ multiwalled fullerene (onion) near the Fermi level. The analytical expressions for the hybridizations of the $\ensuremath{\pi}$ Orbitals on the fullerene shells were derived. The difference between the Fermi levels of individual fullerenes is obtained. The highest occupied Molecular Orbital--lowest unoccupied Molecular Orbital energy gap for the ${\text{C}}_{60}{\text{-C}}_{240}$ carbon fullerene onion is calculated. The charge transfer from the outer shell to the inner shell in the base state of the onion is determined. Splitting and the shift of the energy levels of the onion as a result of intershell interaction are predicted.

### Weijiu Huang - One of the best experts on this subject based on the ideXlab platform.

• ##### Tribochemistry of ZDDP in Molecular Orbital calculations
Tribology International, 2004
Co-Authors: Weijiu Huang, Xueye Wang
Abstract:

The Molecular Orbital parameters of zinc dialkyldithiophosphate (ZDDP) and several metal-atom-cluster models were calculated. The nature and the strength of the interactions between the ZDDP molecules and different metal surfaces are analysed and discussed with the use of frontier Orbital theory. By comparing the highest occupied Molecular Orbital energy (EHOMO) and the lowest unoccupied Molecular Orbital energy (ELUMO) of the ZDDP and the atoms cluster models of Al6, Cu6, and Fe5, it is concluded that ZDDP behaves as an excellent boundary lubricant additive at the interface with iron. The derived Molecular Orbital parameters illustrate the advantages for tribochemistry studies.

• ##### Tribochemistry of ZDDP in Molecular Orbital calculations
Tribology International, 2004
Co-Authors: Yuanqiang Tan, Weijiu Huang, Xueye Wang
Abstract:

The Molecular Orbital parameters of zinc dialkyldithiophosphate (ZDDP) and several metal-atom-cluster models were calculated. The nature and the strength of the interactions between the ZDDP molecules and different metal surfaces are analysed and discussed with the use of frontier Orbital theory. By comparing the highest occupied Molecular Orbital energy (EHOMO) and the lowest unoccupied Molecular Orbital energy (ELUMO) of the ZDDP and the atoms cluster models of Al6, Cu6, and Fe5, it is concluded that ZDDP behaves as an excellent boundary lubricant additive at the interface with iron. The derived Molecular Orbital parameters illustrate the advantages for tribochemistry studies.

• ##### Molecular Orbital indexes criteria for friction modifiers in boundary lubrication
Tribology International, 2002
Co-Authors: Weijiu Huang, Xueye Wang
Abstract:

Abstract Friction modifiers, due to their adsorption onto metal surfaces, play an important role in boundary lubrication. The Molecular Orbital indexes were used as the criteria to study the interaction between lubricant polar end groups and metal surfaces. By comparing the net electric charge of bonding atoms, the highest occupied Molecular Orbital energy (E HOMO ) and the lowest unoccupied Molecular Orbital energy (E LUMO ) of interactive molecules, one could find that the hydrogen bond strength between alcohol and oxide metal surface which is hydroxylated was stronger than that between a hydroxylated oxide metal surface and ester. On the other hand, the interaction between naked aluminium atoms and ester is stronger than that between naked aluminium atoms and alcohol. Thus, lubricants consisting of alcohol and ester show a combination friction-reducing effect because each of the two components has its own advantages in interaction with the hydroxylated aluminium oxide and naked aluminium atoms on the lubricated interface.

### Donald G Truhlar - One of the best experts on this subject based on the ideXlab platform.

• ##### polarized Molecular Orbital model chemistry 3 the pmo method extended to organic chemistry
Journal of Chemical Theory and Computation, 2013
Co-Authors: Miho Isegawa, Luke Fiedler, Hannah R Leverentz, Yingjie Wang, Santhanamoorthi Nachimuthu, Donald G Truhlar
Abstract:

The polarized Molecular Orbital (PMO) method, a neglect-of-diatomic-differential-overlap (NDDO) semiempirical Molecular Orbital method previously parametrized for systems composed of O and H, is here extended to carbon. We modified the formalism and optimized all the parameters in the PMO Hamiltonian by using a genetic algorithm and a database containing both electrostatic and energetic properties; the new parameter set is called PMO2. The quality of the resulting predictions is compared to results obtained by previous NDDO semiempirical Molecular Orbital methods, both including and excluding dispersion terms. We also compare the PMO2 properties to SCC-DFTB calculations. Within the class of semiempirical Molecular Orbital methods, the PMO2 method is found to be especially accurate for polarizabilities, atomization energies, proton transfer energies, noncovalent complexation energies, and chemical reaction barrier heights and to have good across-the-board accuracy for a range of other properties, including...

• ##### polarized Molecular Orbital model chemistry ii the pmo method
Journal of Chemical Theory and Computation, 2011
Co-Authors: Peng Zhang, Luke Fiedler, Hannah R Leverentz, Donald G Truhlar
Abstract:

We present a new semiempirical Molecular Orbital method based on neglect of diatomic differential overlap. This method differs from previous NDDO-based methods in that we include p Orbitals on hydr...