Ground-state wavefunctions and energies for the helium isoelectronic series through Z equals 10.
He isoelectronic series ground state wave functions and energies, extending configuration interaction method through Z equals 10
Brown, R. T.↗
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Electronic wave functions for atoms. I.
Atomic wave functions determination by configuration interaction method, constructing Slater type orbitals into orthogonal set of smaller dimensions
Bunge, C. F.↗
Doublet electronic states of the benzyl radical.
Doublet electronic states of benzyl radical, discussing configuration-interaction calculations and transition predictions
Phillips, D. H.↗
Relative intensities and exponential decay of a doublet in N V.
Exponential decay and mean lives of lowest P levels in N V measured with beam foil source, noting agreement with theories taking configuration interaction into account
Bashkin, S.↗
Electronic wavefunctions for atoms. III
Electronic wave functions for atoms from atomic configuration-interaction /CI/ expansion for open shell states
Bunge, A.↗
A density matrix approach to multiconfiguration calculations
Density matrix components for multiconfiguration wave functions, constructing N electron /spin free/ Hamiltonian configuration interaction matrix
Harriman, J. E.↗
Zeeman effect of As II.
Spectrograms of As electrodeless-discharge tubes operated in a field of 24,025 G have given Zeeman patterns for 232 As II spectral lines from 2361 to 10,556 A and yielded 80 Lande g factors, of which more than half are new. There is agreement between these and the g values calculated by least-squares fitting for single configurations or for multiconfigurations, where configuration interaction is noticeable. All of the measured g values as well as the energy levels are used in the fitting process.
Li, H.↗
Electron impact excitation and assignment of the low-lying electronic states of CO2
Electron scattering spectra of CO2 are reported in the 7 to 10 eV energy-loss range, at energies of 0.2, 0.35, 0.6, 0.7, and 7.0 eV above threshold, and at a scattering angle of 90 deg. Several new distinct overlapping continua with weak, diffuse bands superimposed are observed to lie in this energy-loss range. The experimental spectra are discussed in the light of recent ab initio configuration-interaction calculations of the vertical transition energies of CO2. The experimental spectra are shown to be consistent with the excitation states of CO2.
Hall, R. I.↗
Spin contamination in unrestricted Hartree-Fock calculations.
Several pi-electron doublets are treated by both the unrestricted Hartree-Fock method and the restricted approximation of Longuet-Higgins and Pople. For two of the molecules, which contain oxygen heteroatoms, serious spin contamination occurs in the UHF wavefunctions, and this negates the usefulness of the single annihilation procedure that is often used for spin-density calculations. The restricted approximation provides a convenient alternative, especially because configuration interaction is easily taken into account.
Schug, J. C.↗
Approximate spin projection of three-component UHF wavefunctions - The states of the pentachlorocyclopentadienyl cation and the croconate dianion, C5O5/2-/
The approximate spin projection method of Amos et al. is extended to handle UHF wave functions having three significant components of differing multiplicity. An expression is given for the energy after single annihilation which differs from that of Amos and Hall. The new expression reproduces the results obtained from a previous exact calculation for which the weights and energies of the components are known. The extended approximate projection method is applied to the pi-electron UHF wave functions for the ground states of the pentachlorocyclopentadienyl cation and the croconate dianion, C5O5(2-). The results indicate a triplet ground state for the former and a singlet ground state for the latter, in agreement with experimental ESR susceptibility measurements for these molecular ions. C5C15(-) cannont be treated by restricted Hartree-Fock theory, due to its open-shell ground state. Incorrect results are obtained for the croconate dianion, if restricted Hartree-Fock theory and singly excited configuration interactions are utilized.
Phillips, D. H.↗
Multiconfiguration self-consistent-field calculation of the dipole moment function of CO/X 1 sigma +/
Using the optimized valence configurations (OVC) multiconfiguration self-consistent-field (MCSCF) method, the dipole moment function for the ground state of CO in the vicinity of the equilibrium internuclear distance has been calculated. The OVC MCSCF calculation results are compared with existing Hartree-Fock and configuration interaction treatments of this molecule at single points and also the dipole moment function deduced from experimental infrared intensities. A general prescription for constructing OVC wavefunctions for diatomic molecules is also presented.
Billingsley, F. P., II↗
A nearly exact MCSCF+CI calculation of the dissociation energy of OH
The dissociation energy and dipole moment of the ground state of OH have been obtained with a newly developed multiconfiguration, self-consistent field plus configuration interaction CDC 7600 computer program. The computed value of the dissociation energy is 4.62 eV, which is within the uncertainty limits for the experimental value of 4.63 plus or minus 0.01 eV. The computed value of the dipole moment is 1.645 D, which is very close to the experimental result of 1.66 plus or minus 0.01 D. The present results are also compared to the data obtained from similar calculations with the BISON-MC computer program developed by Das and Wahl.
Arnold, J. O.↗
Electronic states of Zn2 - Ab initio calculations of a prototype for Hg2
The electronic states of Zn2 are investigated by ab initio polarization configuration-interaction calculations. Molecular states dissociating to Zn(1S) + Zn(1S, 3P, 1P) and Zn(3P) + Zn(3P) are treated. Important effects from states arising from Zn(+)(25) + Zn(-)(2P) are found in the potential-energy curves and electronic-transition moments. A model calculation for Hg2 based on the Zn2 curves and including spin-orbit coupling leads to a new interpretation of the emission bands in Hg vapor.
Hay, P. J.↗
Theoretical investigation of protonated carbon dioxide
The equilibrium structure of CO2H(+) has been obtained from self-consistent field and configuration interaction wave functions. Only one stable form has been found, a linear O-C-O chain with the hydrogen bonded to oxygen and slightly off axis, in analogy with known isoelectronic species. A second structure protonated at carbon, which has been inferred from mass spectrometric studies, is found to be unstable with respect to spontaneous rearrangement. The proton affinity of CO2 is calculated to be 136 kcal/mole, in reasonable agreement with the most recent experimental value.
Green, S.↗
MCSCF + Cl wavefunctions and properties of the X2-Pi and A2-Pi states of ClO
A multiconfiguration, self-consistent field plus configuration-interaction calculation has been performed on the X2-Pi and A2-Pi electronic states of ClO. The values of certain molecular properties computed from the wavefunctions agree well with those from experiment. The sum of the squares of the computed electronic transition moments between the X2-Pi and A2-Pi states at 3.07 bohr is 1.75 a.u., which corresponds to the experimental result of 1.58 plus or minus 0.20 a.u. The computed ground state dipole moment at the experimental equilibrium separation is 1.232 D, which compares well with two experimental results of 1.18 plus or minus 0.12 and 1.239 plus or minus 0.010 D. The value of the computed dissociation energy is 2.75 eV, which agrees well with the experimental value of 2.803 plus or minus 0.001 eV.
Arnold, J. O.↗
Photoabsorption in formaldehyde
Theoretical studies of the vertical electronic dipole excitation and ionization spectra in molecular formaldehyde are reported. The investigations relied on configuration-interaction calculations and moment-theory techniques. A double-zeta basis of contracted Gaussian-lobe functions supplemented with appropriate polarization and bond functions was used to construct Fock spectra in C(2 nu) symmetry for certain states near the ground state equilibrium geometry. The ionization energies, discrete vertical transition frequencies, and oscillator strengths for occupied and vertical Fock orbitals are in general accord with experimental determinations and other theoretical calculations. Stieltjes and Chebyshev vertical electronic photoionization profiles were calculated and found to be in good agreement with appropriately averaged photoionization-mass spectrometric measurements of the cross section for parent H2CO(+) ion production.
Langhoff, P. W.↗
A theoretical study of the electronic transition moment for the C2 Swan band system
Large-scale self-consistent-field plus configuration-interaction calculations have been performed for the a 3Pi u and d 3Pi g states of C2. The theoretical potential curves are in good agreement with those found by a Klein-Dunham analysis of measured molecular constants in terms of shape and excitation energy. The sum of the squares of the theoretical transition moments between the states at 2.44 bohr is 4.12 a.u. which agrees with the results of shock tube measurements. The variation in the sum of the squares of the theoretical moments with internuclear separation agrees with the values of Danylewych and Nicholls (1974). Based on the data for C2 and mother molecules, it is suggested that CI calculations using near Hartree-Fock quality Slater basis sets produce highly reliable transition moments.
Arnold, J. O.↗
Theoretical study of collinear Be + FH/nu1/ yields BeF/nu2/ + H
The potential energy surface for collinear Be + FH yields BeF + H was studied at various levels of ab initio approximation. A final surface was obtained from a first order configuration interaction wave function, using the iterative orbital method and a medium-sized basis of Slater atomic functions. The exothermicity is computed to be 6 kcal/mole; the barrier height is predicted to be about 28 kcal/mole at a geometry where both internuclear separations are extended by about 0.4 bohr from their asymptotic equilibrium values. This surface differs qualitatively from simple LEPS models.
Schor, H.↗