Cruciforms’ Polarized Emission Confirms Disjoint Molecular Orbitals and Excited States

2012 ◽  
Vol 14 (4) ◽  
pp. 1000-1003 ◽  
Author(s):  
Matthew N. Gard ◽  
Anthony J. Zucchero ◽  
Gregory Kuzmanich ◽  
Christian Oelsner ◽  
Dirk Guldi ◽  
...  
Keyword(s):  
Excited States ◽  
Molecular Orbitals ◽  
Polarized Emission

Excitation Energies from a Partially Spin-Restricted Wave Function

2007 ◽  
Vol 3 (1) ◽  
pp. 65-69 ◽  
Author(s):  
V.N. Glushkov
Keyword(s):  
Wave Function ◽  
Excited States ◽  
Electron Correlation ◽  
Electronic Excitation ◽  
Slater Determinant ◽  
Molecular Orbitals ◽  
Reference Configuration ◽  
Excitation Energies ◽  
Hartree Fock ◽  
Natural Base

A singe Slater determinant consisting of restricted and unrestricted, in spins, parts is proposed to construct a reference configuration for singlet excited states having the same symmetry as the ground one. A partially restricted Hartree-Fock approach is developed to derive amended equations determining the spatial molecular orbitals for singlet excited states. They present the natural base to describe the electron correlation in excited states using the wellestablished spin-annihilated perturbation theories. The efficiency of the proposed method is demonstrated by calculations of electronic excitation energies for the Be atom and LiH molecule.

Localized molecular orbitals for excited states of polyenals, polyendials, and polyenones

2003 ◽  
Vol 97 (1) ◽  
pp. 688-699 ◽  
Author(s):  
J. Pitarch-Ruiz ◽  
S. Evangelisti ◽  
D. Maynau
Keyword(s):  
Excited States ◽  
Molecular Orbitals ◽  
Localized Molecular Orbitals

scholarly journals Ab Initio Analysis of Exchange Interactions in [V2O(BIPY)4CL2]2+ Complex

2008 ◽  
Vol 3 (1) ◽  
pp. 112-117
Author(s):  
Ivan Ogurtsov ◽  
Andrei Tihonovschi
Keyword(s):  
Ab Initio ◽  
Excited States ◽  
Ground State ◽  
Exchange Interactions ◽  
Boltzmann Distribution ◽  
Molecular Orbitals ◽  
Vanadium Complex ◽  
Ferromagnetic Interaction ◽  
Ci Calculations ◽  
D Orbitals

In this work an ab initio analysis of the binuclear vanadium complex [V2O(bipy)4Cl2]2+ electronic structure is performed. The ground state was calculated to be a quintet, which means a ferromagnetic interaction between centers. The orbitals participating in exchange interaction according to ROHF+CI calculations are two molecular orbitals consisting of vanadium d-orbitals and two molecular orbitals with main contributions from p-orbitals of bipyridine ligands perpendicular to V-V axis, vanadium d- and p-orbitals and μ-oxygen p-orbital. Calculated energy values of the multielectronic states are placed in accordance with Lande rule. The value of magnetic moment at 293K calculated for the complex in vacuum taking into consideration the Boltzmann distribution and the energies of the excited states is 3.95BM which is in accordance with experimental value of 3.99BM (for complex in acetone).

General-Model-Space State-Universal Coupled-Cluster Method: Excited States of Ozone

2005 ◽  
Vol 70 (6) ◽  
pp. 755-770 ◽  
Author(s):  
Xiangzhu Li
Keyword(s):  
Excited States ◽  
General Model ◽  
Model Space ◽  
Molecular Orbitals ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Normal Range ◽  
Cluster Calculations ◽  
Space State ◽  
Cluster Methods

The low-lying excited states of ozone are investigated using the recently developed general-model-space state-universal coupled-cluster methods and the results are compared with other multireference coupled-cluster and spin-adapted unitary-group coupled-cluster approaches. The role played by the choice of different molecular orbitals in coupled-cluster calculations is also explored. It is found that the low-lying 1,3B2 states are particularly sensitive to the choice of the molecular orbitals. This observation explains some significant differences between the results obtained with spin-adapted and spin-non-adapted multireference coupled-cluster approaches, as documented by earlier studies. The use of appropriate orbitals brings the effect of spin-adaptation to its normal range.

Molecular orbital calculations on dinitrogen trioxide, N2O3

1977 ◽  
Vol 30 (12) ◽  
pp. 2613 ◽  
Author(s):  
IJ Doonan ◽  
RGAR Maclagan
Keyword(s):  
Molecular Orbital ◽  
Excited States ◽  
Molecular Orbital Calculation ◽  
Molecular Orbitals ◽  
Basis Set ◽  
Molecular Orbital Calculations ◽  
Localized Molecular Orbitals ◽  
Expansion Technique ◽  
Doubly Excited ◽  
Slater Basis

A minimal Slater basis set molecular orbital calculation on dinitrogen trioxide, N2O3, is reported. In the evaluation of integrals, non-NDDO integrals were calculated by the 3G/s expansion technique. Analysis of the wave function obtained shows weak bonding between the nitrosyl and nitro fragments and a very weak attractive interaction between the cis- oxygens. The molecular orbitals for N2O3 were expanded in terms of the NO and NO2 molecular orbitals. A correlation diagram linking the N2O3 orbitals with the NO and NO2 orbitals is presented. The localized molecular orbitals for N2O3 are analysed. A configuration interaction calculation involving the ground state and nine doubly excited state configurations is reported. Two excited states have significant contributions. A comparison is made between the results obtained by using a 3G/S expansion and a calculation using a 2G/S expansion.

scholarly journals Excited States of Molecules Studied by Electron Spectroscopy. Resonances and Their Relations with Molecular Orbitals.

1996 ◽  
Vol 45 (6) ◽  
pp. 267-280
Author(s):  
Hiroshi TANAKA ◽  
Kiyoshi UEDA ◽  
Mitio INOKUTI
Keyword(s):  
Excited States ◽  
Electron Spectroscopy ◽  
Molecular Orbitals

Molecular Orbitals for Excited States

1974 ◽  
Vol 10 (6) ◽  
pp. 337-339 ◽  
Author(s):  
Sten Lunell ◽  
Peter Lindner
Keyword(s):  
Excited States ◽  
Molecular Orbitals

scholarly journals Quantum Mechanics / Extremely Localized Molecular Orbital Embedding Strategy for Excited-States. 2. Coupling to the Equation-of-Motion Coupled Cluster Method

2020 ◽  
Author(s):  
Giovanni Macetti ◽  
Alessandro Genoni
Keyword(s):  
Quantum Mechanics ◽  
Molecular Orbital ◽  
Excited States ◽  
Quantum Chemical ◽  
Computational Cost ◽  
Equation Of Motion ◽  
Molecular Orbitals ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Localized Molecular Orbitals

Equation-of-Motion Coupled Cluster with single and double excitations (EOM-CCSD) is currently one of the most accurate quantum chemical methods for the investigation of excited-states, but its non-negligible computational cost unfortunately limits its application to small molecules. To extend its range of applicability, one possibility consists in its coupling with the so-called multi-scale embedding techniques. Along this line, in this work we propose the interface of the EOM-CCSD method with the recently developed quantum mechanics / extremely localized molecular orbital (QM/ELMO) strategy, an approach where the chemically relevant region of the investigated system is treated at fully quantum chemical level (QM region), while the remaining part (namely, the chemical environment) is described through transferred and frozen extremely localized molecular orbitals (ELMO subsystem). In order to determine capabilities and limitations of the novel EOM-CCSD/ELMO approach, some validation tests were properly designed and carried out. They indicated that the new approach is particularly useful and efficient in describing local electronic transitions in relatively large systems, for both covalently and non-covalently bonded QM and ELMO regions. In particular, it has been shown that, including only a limited number of atoms in the chemically active subunit, the ELMO-embedded computations enable the reproduction of excitation energies and oscillator strengths resulting from full EOM-CCSD calculations within the limit of chemical accuracy, but with a significantly reduced computational cost. Furthermore, despite the approximation of an embedding potential given by frozen extremely localized molecular orbitals, it was observed that the new strategy is able to satisfactorily account for the effects of the environment.

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