scholarly journals Koopmans’s theorem in the restricted open-shell Hartree–Fock method. II. The second canonical set for orbitals and orbital energies

2010 ◽  
Vol 132 (18) ◽  
pp. 184110 ◽  
Author(s):  
Ernest R. Davidson ◽  
Boris N. Plakhutin
Keyword(s):  
Open Shell ◽  
Hartree Fock ◽  
Orbital Energies

Analytic energy gradients for open-shell coupled-cluster singles and doubles (CCSD) calculations using restricted open-shell Hartree—Fock (ROHF) reference functions

1991 ◽  
Vol 182 (3-4) ◽  
pp. 207-215 ◽  
Author(s):  
Jürgen Gauss ◽  
Walter J. Lauderdale ◽  
John F. Stanton ◽  
John D. Watts ◽  
Rodney J. Bartlett
Keyword(s):  
Open Shell ◽  
Coupled Cluster ◽  
Hartree Fock ◽  
Reference Functions

MO-Theoretical Studies on a Model Complex for Deoxymyoglobin

1998 ◽  
Vol 53 (9) ◽  
pp. 755-765
Author(s):  
Christian Kollma ◽  
Sighart F. Fischer ◽  
Michael C. Böhm
Keyword(s):  
High Spin ◽  
Ground State ◽  
High Spin State ◽  
Open Shell ◽  
Spin States ◽  
Hartree Fock ◽  
Intermediate Spin ◽  
Model Complex ◽  
Out Of Plane ◽  
Overlap Method

AbstractThe origin of the displacement of the Fe atom in deoxymyoglobin with respect to the porphyrin plane in the high-spin state is examined by a qualitative molecular orbital (MO) analysis on the extended Hückel level. We find that attachment of a fifth ligand (imidazole in our model complex) to Fe(II)porphyrin favors the out-of-plane shift due to a strengthening of the bonding interaction between Fe and the nitrogen of the imidazole ligand. This results in a high-spin (5 = 2) ground state with Fe shifted out-of-plane for the five-coordinate complex instead of an intermediate spin ground state (5 = 1) with Fe lying in the plane for four-coordinate Fe(II)porphyrin. The relative energies of the different spin states as a function of the distance between Fe and the porphyrin plane are evaluated using an ROHF (restricted open shell Hartree-Fock) version of an INDO (intermediate neglect of differential overlap) method. We observe a level crossing between high-spin and intermediate spin states whereas the low-spin (5 = 0) state remains always higher in energy.

scholarly journals Evaluation of the one electron expectation values for different wave function of Be atom

2007 ◽  
Vol 4 (3) ◽  
pp. 393-396
Author(s):  
Baghdad Science Journal
Keyword(s):  
Wave Function ◽  
Slater Determinant ◽  
Open Shell ◽  
Expectation Values ◽  
Electronic Density ◽  
Expectation Value ◽  
Hartree Fock ◽  
Shell System ◽  
Electronic Wave Function ◽  
The One

The aim of this work is to evaluate the one- electron expectation value from the radial electronic density function D(r1) for different wave function for the 2S state of Be atom . The wave function used were published in 1960,1974and 1993, respectavily. Using Hartree-Fock wave function as a Slater determinant has used the partitioning technique for the analysis open shell system of Be (1s22s2) state, the analyze Be atom for six-pairs electronic wave function , tow of these are for intra-shells (K,L) and the rest for inter-shells(KL) . The results are obtained numerically by using computer programs (Mathcad).

Ab initio predictions of the zero field splittings and the singlet–triplet transition strengths for the n → π* transition of selenoformaldehyde

1993 ◽  
Vol 71 (10) ◽  
pp. 1706-1712 ◽  
Author(s):  
D.C. Moule ◽  
L. Chantranupong ◽  
R.H. Judge ◽  
D.J. Clouthier
Keyword(s):  
Energy Levels ◽  
Random Phase ◽  
Open Shell ◽  
Oscillator Strengths ◽  
Basis Set ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Hartree Fock ◽  
Lower Valence ◽  
Polarization Functions

The energy levels of the lower valence and Rydberg states of selenoformaldehyde, CH2Se, have been calculated by the SCF/CI method. Wavefunctions for the ROHF (restricted open shell Hartree–Fock) states were obtained with the Binnings–Curtis double-ζ basis set, augmented with Rydberg and polarization functions. Configuration interaction was applied to the parent configurations, PCMO (parent configuration molecular orbital). Oscillator strengths were evaluated for the allowed electric dipole transitions by the RPA (random phase approximation), and SOPPA (second-order polarization propagator approximation) methods. The spin-orbit contribution to the zero field splitting of the first triplet state, 3A2(n,π*) as well as the oscillator strengths to the three spin components were calculated by perturbation theory. These calculations predict that the Sx, Sy, and Sz components are shifted by −96.091,−96.707, and + 29.167 cm−1, respectively, from their unperturbed position. The oscillator strengths for the three components fx, fy, and fz of the 3A2(n,π*) ← 1A1(g.s.) transition were calculated to be 3.45 × 10−7, 1.15 × 10−7, and 173.0 × 10−7.

Spin adapted restricted Hartree–Fock reference coupled cluster theory for open shell systems

1994 ◽  
Vol 100 (5) ◽  
pp. 3706-3716 ◽  
Author(s):  
Pavel Neogrády ◽  
Miroslav Urban ◽  
Ivan Hubac̆
Keyword(s):  
Open Shell ◽  
Coupled Cluster ◽  
Coupled Cluster Theory ◽  
Cluster Theory ◽  
Hartree Fock

scholarly journals Vibrationally and Spin-Orbit-Resolved Inner-Shell X-ray Absorption Spectroscopy of the NH+ Molecular Ion: Measurements and ab Initio Calculations

Atoms ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 67
Author(s):  
Stéphane Carniato ◽  
Jean-Marc Bizau ◽  
Denis Cubaynes ◽  
Eugene T. Kennedy ◽  
Ségolène Guilbaud ◽  
...  
Keyword(s):  
Ab Initio ◽  
Density Functional ◽  
Theoretical Calculations ◽  
High Sensitivity ◽  
Open Shell ◽  
Field Configuration ◽  
High Spectral Resolution ◽  
Spin Orbit ◽  
Molecular Ion ◽  
Hartree Fock

This article presents N2+ fragment yields following nitrogen K-shell photo-absorption in the NH+ molecular ion measured at the SOLEIL synchrotron radiation facility in the photon energy region 390–450 eV. The combination of the high sensitivity of the merged-beam, multi-analysis ion apparatus (MAIA) with the high spectral resolution of the PLEIADES beamline helped to resolve experimentally vibrational structures of highly excited [N1s−1H]*+ electronic states with closed or open-shell configurations. The assignment of the observed spectral features was achieved with the help of density functional theory (DFT) and post-Hartree Fock Multiconfiguration Self-Consistent-Field/Configuration Interaction (MCSCF/CI) ab-initio theoretical calculations of the N1s core-to-valence and core-to-Rydberg excitations, including vibrational dynamics. New resonances were identified compared to previous work, owing to detailed molecular modeling of the vibrational, spin-orbit coupling and metastable state effects on the spectra. The latter are evidenced by spectral contributions from the 4Σ− electronic state which lies 0.07 eV above the NH+2Π ground state.

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