Lithium molecule

Ishiguro, E., Kayama, K., Kotani, M., and Mizuno, Y., J. Phys. Soc. Japan 12, 1355, Electronic structure of simple homonuclear diatomic molecules. II. Lithium molecule. ... 

Fig. 7.—Energy curves for the lithium molecule-ion, with consideration of the s-p separation.

James also carried out a treatment of the lithium molecule-ion with use of 25 orbitals and explicit consideration of the four K electrons, obtaining the energy value —0.304 e. v. at r = 2.98 A. (this being not necessarily the minimum point of the curve). Our curve for an 5 bond similarly gives a very small energy value, — 0.22 e. v., at this value of r. The calculations described above indicate that the principal source of inaccuracy in these treatments is the assumption that the bonds are 5 bonds, and that the consideration of s-p hybridization makes a great improvement. 

Fig. 8.—-The ratio of coefficients of p and s orbitals for the normal state of the lithium molecule-ion.

The energy of the one-electron bond in the lithium molecule ion is calculated with consideration of the s-p separation to be 1.19 e. v and the hybrid bond orbital involved is shown to involve about equal contributions from the 25 and 2p orbitals of the lithium atom. 

It was already established that pure ethyl-" " and f-butyllithium exist as six- and fourfold polymers, respectively, in benzene solution. Apparently, C—Li bond cleavage takes place in this solvent leading to an exchange of alkyl groups between polymeric organo-lithium molecules when both compounds are present. The products are believed to be electron-deficient polymers of the type (EtLi) (f-BuLi) , wha-e m is a small number such as 4 or 6. ... 

For example, in metals, because of their large electrical conductivity, it seems that at least some of the electrons can move freely through the bulk of the metal, while the core electrons remain in their atomic orbital, similar to the isolated atoms forming the metal. For example, let us take into account the formation of a linear array of lithium atoms from individual lithium atoms Li-Li Li-Li-Li Li-Li-Li-Li. Then, the first stage is the formation of a lithium molecule, Li2. This molecule is analogous to the hydrogen molecule, H2 [15,19], In the formation of the H2 molecule, two MOs are formed, that is, the bonding MO... 

It is fairly well understood that alkyl lithiums form rather stable aggregates in which carbon-lithium bond order is maximized by the utilization of all valence orbitals of lithium.(1) Polystyryl lithium molecules are mostly dimeric in solution.(1.3,4) This has been generally accepted by all the investigators.TlT However, association numbers of two(6) and four(Z T has been reported for polydienes. Two methods were used in determining these values, viz., light scattering measurements (in vacuo) and viscosity measurements. 

Figure 2 gives the variation of the function along the line of two neighboring nuclei in several molecules. This figure clearly shows that for the homopolar bonds (the central bond of naphthalene, the hydrogen molecule, the lithium molecule) the result of the chemical bond is an increase of electrons between" the nuclei, while for the heteropolar bond (LiH) there is a transfer of charge from one atom towards the others. 

In the ground state of the lithium molecule, Lia, if each of the nuclei is surrounded by a concentric sphere of 1.53 atomic units radius, then it can be shown that there is a 96 per cent probability of finding only two electrons of paired spin in one of the spheres, and a 90 per cent probability of finding a pair between the spheres. 

In an attempt to check the performance of the HPHF model for determining singlet excited states, most of the excited states of the lithium molecule, Lij, were determined as a function of the nuclear separation, and their spectroscopic constants evaluated. In this aim, the standard 6-31IG basis set was used for all of them [15. ... 

Table 2. The equilibrium distances, Re, (in A), the force constants, Wei (>n cm ) and the anharmonicity constants, uigXe, obtained by using the HPHF and other methods are given for some singlet states of the lithium molecule, together with the experimental values.

Fig. 2. Potential energy curves for some states of the lithium molecule calculated with the 6-Sll( basis set.

Figure 5. A good decomposition in loges for the lithium molecule.

Electronic structure, loges of bonds 6 loges of cores 6 notion of loge 2 of ammonia 9 of benzene 19,20 of diborane 10 of methane 8 of the helium atom 1 of the lithium molecule 6 of the N—H bond 15... 

Together with the concept of loge, Daudel and his group introduced in the literature the notion of "densite electronique differentielle" and applied it initially to the lithium molecule (Roux and Daudel 1955). The differential electronic density was defined as the difference between the electronic density computed at a point of a molecule and the density that existed at the same point if the atoms were side by side without interacting. This notion revealed the effect of the chemical bond on the electronic distribution density (Daudel, Brion, and Odiot 1955 Roirx, Besnainou, and Daudel 1956). A positive difference meant that in the formation of the molecule, there was a region where there was a higher electronic interaction than when the atoms did... 

FIGURE 11.59 Energy Levels of Molecular Orbitals In Lithium Molecules... 

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