Low-Lying Electronic States of the Nickel Dimer

The generalized Van Vleck second order multireference perturbation theory (GVVPT2) method was used to investigate the low-lying electronic states of Ni2. Because the nickel atom has an excitation energy of only 0.025 eV to its first excited state (the least in the first row of transition elements), Ni2 has a particularly large number of low-lying states. Full potential energy curves (PECs) of more than a dozen low-lying electronic states of Ni2, resulting from the atomic combinations 3F4 + 3F4 and 3D3 + 3D3, were computed. In agreement with previous theoretical studies, we found the lowest lying states of Ni2 to correlate with the 3D3 + 3D3 dissociation limit, and the holes in the d-subshells were in the subspace of delta orbitals (i.e., the so-dubbed δδ-states). In particular, the ground state was determined as X 1Γg and had spectroscopic constants: bond length (Re) = 2.26 Å, harmonic frequency (ωe) = 276.0 cm−1, and binding energy (De) = 1.75 eV; whereas the 1 1Σg+ excited state (with spectroscopic constants: Re = 2.26 Å, ωe = 276.8 cm−1, and De = 1.75) of the 3D3 + 3D3 dissociation channel lay at only 16.4 cm−1 (0.002 eV) above the ground state at the equilibrium geometry. Inclusion of scalar relativistic effects through the spin-free exact two component (sf-X2C) method reduced the bond lengths of both of these two states to 2.20 Å, and increased their binding energies to 1.95 eV and harmonic frequencies to 296.0 cm−1 for X 1Γg and 297.0 cm−1 for 1 1Σg+. These values are in good agreement with experimental values of Re = 2.1545 ± 0.0004 Å, ωe = 280 ± 20 cm−1, and D0 = 2.042 ± 0.002 eV for the ground state. All states considered within the 3F4 + 3F4 dissociation channel proved to be energetically high-lying and van der Waals-like in nature. In contrast to most previous theoretical studies of Ni2, full PECs of all considered electronic states of the molecule were produced.

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Theoretical electronic investigation of the low-lying electronic states of the LuF molecule

Canadian Journal of Physics ◽

10.1139/p09-077 ◽

2009 ◽

Vol 87 (11) ◽

pp. 1163-1169 ◽

Cited By ~ 7

Author(s):

Y. Hamade ◽

F. Taher ◽

M. Choueib ◽

Y. Monteil

Keyword(s):

Ground State ◽

Electronic States ◽

Electronic Energy ◽

Wave Number ◽

Spectroscopic Constants ◽

Complete Active Space ◽

Consistent Field ◽

Self Consistent ◽

Self Consistent Field ◽

Calculated Potential Energy

The theoretical electronic structure of the LuF molecule is investigated, using the Complete Active-Space Self-Consistent Field CASSCF and the MultiReference Configuration Interaction MRCI methods. These methods are performed for 26 electronic states in the representation 2s+1Λ(+/−), neglecting spin–orbit effects. Spectroscopic constants including the harmonic vibrational wave number ωe (cm–1), the relative electronic energy Te (cm–1) referred to the ground state and the equilibrium internuclear distance Re (Å) are predicted for all the singlet and triplet electronic states situated below 50 000 cm–1. Calculated potential energy curves are also reported.

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ULTRAVIOLET SPECTRA OF LiH AND LiD

Canadian Journal of Physics ◽

10.1139/p57-129 ◽

1957 ◽

Vol 35 (10) ◽

pp. 1204-1214 ◽

Cited By ~ 75

Author(s):

R. Velasco

Keyword(s):

Excited State ◽

Ground State ◽

Band System ◽

Electronic States ◽

High Dispersion ◽

Dissociation Energies ◽

Near Ultraviolet ◽

Path Lengths ◽

Vibrational Constants ◽

Π State

The absorption spectra of LiH and LiD have been observed in the near ultraviolet with high dispersion and absorbing path lengths up to 16 meters. A new band system has been found in each molecule involving the ground state and a 1Π excited state. Rotational and vibrational analyses of this system have been carried out and rotational and vibrational constants for the upper state have been determined. The observed breaking off of the rotational structure of the bands of this B1Π—X1Σ+ system has been interpreted as due to predissociation by rotation. With this assumption very accurate dissociation limits of the B1Π state have been obtained. From these dissociation limits the dissociation energies of the three known electronic states of LiH and LiD have been calculated. In particular the dissociation energies (D0) of the ground states of LiH and LiD have been found to be 2.4288 ± 0.0002 ev. and 2.4509 ± 0.0010 ev., respectively.

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Applying ab initio Calculations to Theoretically Investigate the Electronic Structure of the Calcium Sulfide Molecule CaS

Modern Applied Science ◽

10.5539/mas.v13n1p1 ◽

2018 ◽

Vol 13 (1) ◽

pp. 1

Author(s):

Hanan Hijazi ◽

Mahmoud Korek

Keyword(s):

Ab Initio ◽

Internuclear Distance ◽

Ground State ◽

Dipole Moments ◽

Electronic States ◽

Rotational Constant ◽

Electronic Energy ◽

Spectroscopic Constants ◽

Calcium Sulfide ◽

Complete Active Space

Using the graphical user interface GABEDIT and the computational chemistry software MOLPRO, the ab initio calculation method has been applied to explore 25 low-lying singlet and triplet electronic states, including the X1Σ+ ground state, of the calcium sulfide molecule CaS in the 2s+1Λ± representation. The multi-reference configuration interaction with Davidson correction (MRCI+Q) and the complete active space self-consistent field (CASSCF) calculations were performed to obtain the potential energy curves in terms of the internuclear distance R. The permanent dipole moments μe of these low-lying electronic states of CaS have been investigated, in addition to the corresponding spectroscopic constants (including the electronic energy with respect to the ground state Te, the equilibrium internuclear distance Re, the harmonic vibrational frequency ωe, the rotational constant Be, and the equilibrium dissociation energy De). In the present work, 19 new singlet and triplet CaS electronic states were investigated for the first time. In addition, it is noticeable that the current results and those already available in literature are in good agreement.

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Calculating Franck Condon Factor and Potential Curves for X2Σ+-A2Π System of BeBr Molecule

International Letters of Chemistry Physics and Astronomy ◽

10.18052/www.scipress.com/ilcpa.52.5 ◽

2015 ◽

Vol 52 ◽

pp. 5-10

Author(s):

Adil Nameh Ayaash

Keyword(s):

Excited State ◽

Potential Function ◽

Dissociation Energy ◽

Ground State ◽

Spectroscopic Properties ◽

Spectroscopic Constants ◽

Condon Factor ◽

Condon Factors ◽

Franck Condon ◽

Potential Curves

The present work concerns by study of spectroscopic properties for Beryllium monobromide BeBr. Franck Condon Factor of BeBr molecule had been calculated theoretically for ground state X2Σ+ and excited state A2Π by special integrals by depending on spectroscopic constants for this molecule. The Dissociation energy and potential curves of this molecule is studied in this work by using Hua potential function, the results of potential curves and Franck Condon Factors converge with other researchers results.

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Thermochemical Properties of the Benzynes

Australian Journal of Chemistry ◽

10.1071/ch10126 ◽

2010 ◽

Vol 63 (7) ◽

pp. 1091 ◽

Cited By ~ 22

Author(s):

Paul G. Wenthold

Keyword(s):

Excited State ◽

Ground State ◽

Thermochemical Data ◽

Enthalpies Of Formation ◽

Triplet States ◽

Theoretical Studies ◽

Thermochemical Properties ◽

Starting Point ◽

The Subject ◽

The Absolute

The thermochemical properties of the benzynes have been the subject of investigation for nearly 50 years. This work provides an overview and assessment of all the experimental thermochemical properties that have been reported for the benzynes, or can be derived from reported thermochemical data. These properties include enthalpies of formation and thermochemical values that correspond to formation and dissociation of the benzynes by neutral and ionic processes. Thermochemical values are provided for both the ground-state singlet and the excited-state triplet states of the benzynes. The starting point for all the thermochemical consideration of the benzynes are the enthalpies of formation, which, in this work, are recommend to be 107.3 ± 3.5, 121.9 ± 3.1, and 138.0 ± 1.0 kcal mol–1 for ortho-, meta-, and para-benzyne, respectively (1 kcal mol–1 = 4.184 kJ mol–1). Whereas the paper predominantly focuses on the experimentally determined values, it also provides a comparison with theoretical studies that have examined the absolute thermochemical properties of the benzynes.

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Relativistic Ground and Excited State Energies of a/1-Particle in Hypernuclei Using Woods-Saxon Potentials

Zeitschrift für Naturforschung A ◽

10.1515/zna-1989-1219 ◽

1989 ◽

Vol 44 (12) ◽

pp. 1234-1238 ◽

Cited By ~ 2

Author(s):

C. G. Koutroulos

Keyword(s):

Excited State ◽

Dirac Equation ◽

Excited States ◽

Ground State ◽

Scalar Potential ◽

Binding Energies ◽

Fitting Procedure ◽

Fourth Component ◽

Potential Parameters ◽

Good Agreement

Abstract The relativistic Dirac equation with a scalar potential and the fourth component of a vector potential of the Woods-Saxon shape is solved numerically for potential parameters obtained by a last squares fitting procedure of the ground state binding energies of the Λ in a number of hypernuclei and its binding energies in the ground and excited states (as well as the relevant spacings) for various hypcrnuclei are determined. The results are in very good agreement with the preliminary experimental ones given by Chrien on the basis of the (π+, K+) reaction on nuclei.

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Ab initio calculations of the XI molecules (X = Li, Na, K, Rb) with the ionicity and laser cooling analysis

Canadian Journal of Physics ◽

10.1139/cjp-2018-0908 ◽

2020 ◽

Vol 98 (1) ◽

pp. 45-56 ◽

Cited By ~ 1

Author(s):

Israa Zeid ◽

Rania Al Abdallah ◽

Nayla El-Kork ◽

Mahmoud Korek

Keyword(s):

Dipole Moment ◽

Ab Initio ◽

Laser Cooling ◽

Ground State ◽

Bound States ◽

Electronic States ◽

Spectroscopic Constants ◽

Ionic Character ◽

Canonical Function ◽

Dissociation Energies

For the alkali iodide molecules LiI, NaI, KI, and RbI, ab initio CASSCF/(MRCI+Q) calculations have been employed to investigate the adiabatic potential energy curves and the static dipole moment curves of the low-lying singlet and triplet electronic states in the representation 2S+1Λ(+/−). The spectroscopic constants Te, Re, ωe, Be, αe, the dipole moment μe, and the dissociation energies De have been computed for the bound states. Additionally, the percentage ionic character fionic around the equilibrium position of the ground state and the (2)1Σ+ state has been estimated. Using the canonical function approach, these calculations have been followed by a rovibrational calculation from which the rovibrational constants Ev, Bv, Dv, and the abscissas of the turning points Rmin and Rmax for the investigated bound states are calculated.

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Theoretical Investigation of the Electronic Structure of the Strontium Mono-Sulfide Molecule SrS Using the ab initio Calculation Method

Modern Applied Science ◽

10.5539/mas.v12n8p81 ◽

2018 ◽

Vol 12 (8) ◽

pp. 81

Author(s):

Hanan Hijazi ◽

Mahmoud Korek

Keyword(s):

Ab Initio ◽

Internuclear Distance ◽

Ground State ◽

Dipole Moments ◽

Electronic States ◽

Rotational Constant ◽

Electronic Energy ◽

Spectroscopic Constants ◽

Complete Active Space ◽

Self Consistent Field

AbstractThe ground state and 23 other low-lying singlet and triplet electronic states of the strontium mono-sulfide molecule SrS, in the 2s+1Λ± representation, have been examined by ab initio calculations using the computational chemistry software MOLPRO and the graphical user interface GABEDIT. The potential energy curves, in terms of the internuclear distance R, resulted from the complete active space self-consistent field (CASSCF) and multi-reference doubly and singly configuration interaction (MRDSCI) with Davidson correction (+Q) calculations. The permanent dipole moments (μ) and the spectroscopic constants (Te: the electronic energy with respect to the ground state, ωe: the harmonic frequency, Re: the equilibrium internuclear distance, Be: the rotational constant, De: the equilibrium dissociation energy) have been investigated. The results of this work are in good agreement with the results available in literature. Moreover, for the first time, it was possible to study 20 new singlet and triplet electronic states of SrS molecule.

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