The semiempirical MO method SINDO1, originally suitable for first-and second-row atoms, is extended to transition metals from scandium to zinc. The core Hamiltonian elements in a symmetrically orthogonalized atomic orbital (OAO) basis set are modified and the parameters are optimized to reproduce the experimental geometries, heats of formation, and ionization potentials. An application of the method to a selected number of molecules, as well as a comparison between calculated and experimental data is reported.
A practical scheme for the calculation of excited states of the same symmetry as a given reference state is outlined in the context of the Hartree-Fock method. In order to prevent the excited state from "collapsing" into a lower-lying state, the prediagonalized Fock matrix is diagonalized in a restricted subspace, deleting the component associated with the orbital which participates in the excitation. Computationally, the deletion is accomplished by means of a "big shift" of the associated diagonal element of the prediagonalized Fock matrix. The resulting wave function will not be fully relaxed, but can be shown to be orthogonal to the reference state. The method has been implemented in a molecular UHF program. Applications to the 4u;' hole state of CO and to an excited state of the CuCIi-ion are reported.
O meio de cultivo na base de bicarbonato de sódio usado para produzir a microalga Spirulina em massa e preparado seguinte ZARROUK 1 é meta-estável em contato com a atmosfera. Este fato causa uma grande perda de CO2. Com cálculos e experiências foi determinada a relação entre a pressão parcial de CO2 de soluções de bicarbonato de sódio e o pH da solução. Com pH 10.2 existe um equilíbrio com a concentração de CO2 no ar e desta maneira não há perda de CO2.It is demonstrated by experiments and calculations that the medium used for growing the microalga Spirulina (prepared according to ZARROUK 1 with a resulting pH of 8.7) is highly meta-stable in contact with the atmosphere and is thus loosing considerable amounts of CO2. This economic problem can be avoided by raising the pH of the culture medium to 10.2 where its partial pressure of CO2 corresponds to the partial pressure of CO2 in the atmosphere. The pH shift has practically no influence on the growth of the algae.
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