Papers in this group
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Theoretical methods are reported for ab initio calculations of the adiabatic (Born-Oppenheimer) electronic wave functions and potential energy surfaces of molecules and other atomic aggregates. An outer product of complete sets of atomic eigenstates…
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A method based on first‐order density matrices is proposed to define an atom in a molecule, which is in accord with a previously given definition using density functional theory. The promotion energy Ep is expressed in terms of a defined division…
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Given a homonuclear diatomic molecule AB with an even number of electrons N in the state ψ. What is the state of atom A in the molecule? Using the lemma that 〈ψ‖HA ‖ψ〉/〈ψ‖ψ〉≥E0A where HA is the Hamiltonian for atom A only, having NA =N/2 electrons,…
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In scaled atoms‐in‐molecules theory, variational scaling parameters are introduced into the A‐ and B‐atom eigenfunctions from which molecular basis functions are constructed. All intraatomic contributions to matrix elements are determined rigorously…
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Various formulations (Moffitt's hermitean, non-hermitean, Schmidt- and symmetrically orthogonalized) of the atoms-in-molecules method are applied to the ground state of the H2 molecule. In using energy partitioning with respect to specific…
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A method based on first‐order density matrices is proposed to define an atom in a molecule, which is in accord with a previously given definition using density functional theory. The promotion energy Ep is expressed in terms of a defined division…
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A recent self-consistent field molecular orbital calculation on the nitrogen molecule by Scherr is extended to include configuration interaction. In this way the calculated binding energy De is increased from 1.19 electron volts to 3.29 electron…
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The method of atoms in molecules is modified in such a way as to overcome difficulties encountered in previous calculations. The modified theory is applied to two calculations on the ground state of the hydrogen molecule. The more accurate of the…
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The method of atoms in molecules is investigated in detail for the case of covalent-ionic resonance in the ground state of the hydrogen molecule. It is shown that the method is reliable if, and only if, different orbitals are used to approximate…
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The method of atoms in molecules is investigated in detail for the case of covalent-ionic resonance in the ground state of the hydrogen molecule. It is shown that the method is reliable if, and only if, different orbitals are used to approximate…
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The method of deformed atoms in molecules, proposed previously to remedy deficiencies in the method of Moffitt, is employed to calculate energies of the ground state 1Σg+ and the lower excited states 3Σu+, 1Σu+, and 1IIu of the Li2 molecule. As…
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The method of deformed atoms in molecules, which has been proposed in the preceding paper, is applied to the hydrogen molecule. Two structures, the neutral and ionic ones, are considered. It is assumed that the best approximate functions are made up…
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A modification of Moffit's method of atoms in molecules is here proposed. In this treatment, the modified atomic functions X are introduced, which are made up from the exact eigenfunctions of atoms modified by correction factors so as to take…
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A new treatment of the structure of both planar and twisted forms of ethylene is given. Attention is focused on the unsaturation electrons, to which the method of atoms in molecules is applied. Values are calculated for the location of the N…
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