We use the theory based on the gravitational gauge group G to obtain a spherical symmetric solution of the field equations for the gravitational potentials on a Minkowski space-time. The gauge group G is defined and then we introduce the gauge-covariant derivative Dµ. The strength tensor of the gravitational gauge field is also obtained and a gauge-invariant Lagrangian including the cosmological constant is constructed. A model whose gravitational gauge potentials A α µ (x) have spherical symmetry, depending only on the radial coordinate r is considered and an analytical solution of these equations, which induces the Schwarzschild-de-Sitter metric on the gauge group space, is then determined. All the calculations have been performed by GR Tensor II computer algebra package, running on the Maple V platform, along with several routines that we have written for our model.

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The quantum mechanical and spectral study of two related compounds, namely, 1-p-nitro-benzoyl-benzo[f]quinolinium methylid (BF1) and its cycloadduction derivative 1-p-nitro-benzoyl-2,3-dicarbomethoxy-pyrrolo-[1,2a]-benzo[f]quinoline (BF2) was carried out. Some electro-optical parameters in ground state were estimated by ab initio method. The solvatochromic behavior of the visible spectrum absorption band of the studied molecules in solvents with different macroscopic electro-optical proprieties was analyzed in order to estimate some microscopic molecular parameters of BF1 and BF2 in the excited state. Thus it was evidenced that, by excitation, the increase of BF1dipole moment and electric polarizability occurred while for BF2 either the increase or the decrease of these two parameters was found. The study is of practical importance for further synthesis of new derived compounds with potential applications in life sciences.