Results 271 to 280 of about 129,793 (295)

Multireference configuration interaction study on spectroscopic parameters and molecular constants of PO and PO⁺

International Journal of Quantum Chemistry, 2011
AbstractThe highly accurate valence internally contracted multireference configuration interaction (MRCI) approach has been employed to investigate the potential energy curves (PECs) for the X2Π, b4Σ−, C2Σ− states of PO and the X1Σ+ state of PO+. For these electronic states, the spectroscopic parameters of the isotopes (P16O, P18O, P16O+, and P18O ...
Jin‐Feng Sun, Jie‐Min Wang, De‐Heng Shi   +2 more
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MRCI study on the spectroscopic parameters and molecular constants of the X1Σ+, a3Σ+, A1Π and C1Σ− electronic states of the SiO molecule

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2012
The potential energy curves (PECs) of the X(1)Σ(+), a(3)Σ(+), A(1)Π and C(1)Σ(-) electronic states of the SiO molecule are studied using an ab initio quantum chemical method. The calculations have been made employing the complete active space self-consistent field (CASSCF) method, which is followed by the valence internally contracted multireference ...
Deheng, Shi, Wentao, Li, Jinfeng, Sun, Zunlue, Zhu   +3 more
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Studies in Molecular Structure. V. Computed Spectroscopic Constants for Selected Diatomic Molecules of the First Row

The Journal of Chemical Physics, 1961
Limited LCAO MO functions were computed for several diatomic molecules at four different values of the internuclear distance near Re, and the corresponding total energies fitted to a third degree polynomial in R. Spectroscopic constants ωe, ωexe, Be, αe, Re, ke were derived from the resulting potential curve and compared to observed values.
S. Fraga, B. J. Ransil
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Spectroscopic parameter and molecular constant investigations on X2Σ+ and A2Πi states of 12C14N, 12C15N, 13C14N and 13C15N species

Journal of Molecular Structure: THEOCHEM, 2010
Abstract The potential energy curves of X 2 Σ + and A 2 Π i states of CN radical have been investigated using the complete active space self-consistent-field method followed by the highly accurate valence internally contracted multireference configuration interaction approach in combination with the cc-pV5Z basis set.
Deheng Shi, Hui Liu, Xiaoniu Zhang, Jinfeng Sun, Zunlue Zhu, Yufang Liu   +5 more
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Spectroscopic analysis of molecular structures by theoretical calculations based upon Slater's shielding constants

Journal of Molecular Structure, 1992
Abstract Shielding constants of nuclear charge can be considered as a principle unifying the theory of BOHR and the WAVE-MECHANICAL theory. Spectroscopic maxima are explained in this paper in terms of molecular-orbital electron transitions in comparison with calculations of wave numbers, by the aid of shielding constants.
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Accurate ab initio prediction of molecular geometries and spectroscopic constants, using SCF and MP2 energy derivatives

Journal of the Chemical Society, Faraday Transactions 2, 1987
The evaluation of analytic gradients and higher derivatives has had a tremendous impact on quantum chemistry. Although self-consistent field (SCF) first derivatives and higher derivatives are now routinely evaluated as ‘black-box’ procedures, derivatives of correlated wavefunctions are not.
Nicholas C. Handy, Jeffrey F. Gaw, Emmanuel D. Simandiras   +2 more
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Multireference Coupled-Cluster Approach to Spectroscopic Constants: Molecular Geometries and Harmonic Frequencies

1992
The coupled-cluster (CC) method,1–4 originally designed for closed-shell systems, has been extended to include open-shell systems, which cannot be described adequately by a single determinant.5–22 The basic approach of the multireference method is to define an effective Hamiltonian in a low-dimensional model (or P) space, with eigenvalues approximating
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Molecular potentials from CARS photofragment spectroscopy: spectroscopic constants and potential energy curve for oxygen(a1.DELTA.g)

The Journal of Physical Chemistry, 1987
The authors describe the use of CARS spectroscopy of photofragments as a means of obtaining extensive spectroscopic constants and accurate potential curves. UV photodissociation of ozone yields O/sub 2/(a/sup 1/..delta../sub g/) in nu = 0-6 and J = 0-50.
Jong Chen. Nieh, James J. Valentini
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Computed Potential Curve and Spectroscopic Constants for Beryllium Oxide Ground State in Molecular Orbital Approximation

The Journal of Chemical Physics, 1964
A set of single-configuration self-consistent field molecular orbital wavefunctions for the 1Σ ground state of BeO is presented. A potential curve which is approximately 0.3 eV above the Hartree—Fock potential curve for the molecule is presented, together with the results of a spectroscopic analysis on it.
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Spectroscopic constants and molecular properties of , A2Πu, and D2Πg electronic states of the ion

Computational and Theoretical Chemistry, 2011
Deheng Shi, Wei Xing, Jinfeng Sun, Zunlue Zhu, Yufang Liu   +4 more
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