Antisymmetric molecular

Ross, I. G., Trans. Faraday Soc. 48, 973, Calculations of the energy levels of acetylene by the method of antisymmetric molecular orbitals, including a—7r-interaction."... 

The electronic structure of this compd detd by the method of antisymmetrical molecular orbitals (ASMO) has been reported by Paoloni (Ref 4)... 

Vladimiroff, in a study of carbon—proton coupling in ethylene, has considered the familiar Pople-Santry expression for coupling constants in terms of contributions due to symmetric and antisymmetric molecular states. If the symmetric and antisymmetric parts are denoted... 

In contrast to 3, which can bind one electrophile at each Fe atom as in 6, the doubly bridged anion 4 is best suited to bind only one bridging group as in 7. In effect, the two electron pairs of 4 used to bind to an electrophile can be described by symmetric and antisymmetric molecular orbitals centered at the metal atoms and directed to the vacant bridging position (9). Hence, a wide variety of acceptor groups... 

Even if no integral parametrizations are introduced and the HF equations are all correctly solved, the method eventually turns out to be theoretically incomplete. Despite the correct treatment of electronic exchange (X) within Hartree-Fock theory, electronic correlation (C) is totally missing. This is easily shown for the case of the H2 molecule in which we use the bonding solution of the H2 molecular ion ( + = cr from Equation (2.15)) to build up an antisymmetrized molecular wave function. This means that we put both electrons (ri and rz) of the H2 molecule into the same ip+ orbital, and Pauli s principle is obeyed by means of the ct/ spinors. Neglecting orbital overlap and any pre-factors, for simplicity, the so-called Hund-Mulliken [124] (another name... 

Interpretation in terms of thermal population of symmetrical and antisymmetrical molecular orbitals, McLachlan calculations of spin densities. ... 

FIGURE 1.9 Twofold axis (C2) symmetric and antisymmetric molecular orbitals. 

As above, the active orbitals are called ([) and ( )a on one chromophore (A) and ( )j and ([), on the other chromophore (B) (Eigure 14.4). We assume that the two chro-mophores are identical, and related by symmetry operations. The ground state wave fnnction contains symmetric and antisymmetric molecular orbitals (MO) of the type ([) <[)j and <[)j <[), . Index i and a belong to center A, and j and b to center B. We inclnde only the relevant orbitals and write the ground state wave fnnction as... 

Appendix 11 The Coefficients of All Antisymmetric Molecular Orbitals of the Tetracene Derivative C20H14... 

The coefficients a, b, c of antisymmetric molecular orbitals of the tetracene derivative C2oH,4 satisfy the same snm rules that hold for antisymmetric molecular orbitals of hexatriene in Table AlO.l in Appendix 10 that the magnitudes of the coefficients of symmetric and antisymmetric eigenvectors have the same magnitudes and only differ in their signs. 

In the monoalkylcyclopentadienyl radical, the degeneracy of the symmetric and antisymmetric molecular orbitals of the n system is broken by electron release from the substituent which destabilizes the symmetric MO, which becomes singly occupied, as indicated by the large hyperfine couping constants at Hi and Hg 4 and the small values at Hz.s- ... 

The terminal 2p orbitals of an antisymmetric molecular orbital have the positively signed lobes on the opposite sides of the molecule. Thus, the orbitals must rotate in the same direction to form a a bond. The rotation is conrotatory. 

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