Structural features of some small carbonyls in the ^1,3nπ states: An mcscf study

Abstract

Structural features of a series of tetraatomic carbonyls in the '%7r* states are studied by using a recently proposed MCSCF algorithm at the m / 2 level. The computed geometrical parameters and the inversion barrier heights agree quite well with the available experimental or ab initio theoretical data. The calculated transition energies turn out to be somewhat lower than the expenmental counterparts. The specific MCSCF algorithm used is found to have excellent convergence properties.

Basicity of some proto-typical carbonyls in the ground and some low lying excited states: Application of the orthogonal gradient method of orbital optimization in an INDO-MC-SCF framework-I

“…In ( 2 iteratively by a variant of the orthogonal gradient method (OGM) of orbital optimization (Mukherjee 1978;Golebiewski et al 1979;Mukherjee 1979, 1981;Das et al 1986Das et al , 1989. OGM involves the construction of the following iterative sequence:…”

“…Ab-initio calculation of excited state PA being difficult, we have undertaken elaborate investigations on the basicity of some small carbonyl chromophores in a number of low-lying excited states within the framework of our INDO-(MC)-SCF orthogonal gradient method of orbital and geometry optimization (INDO-MC-SCF-OGM). The reason for selecting this particular methodology lies in its success in the calculation of structural features of small carbonyl and thiocarbonyl systems in excited states (Das et al 1986(Das et al , 1989. Our investigations aim at covering broadly the following aspects: (i) The variations in proton affinities of X2 C--O type ofcarbonyls (X=H, F) from state to state.…”

The behavior of quantum chemical bond order in the vicinity of a saddle point on the reaction path

“…16 Control reactions proved that all observations were due to the reactivity of the isoalloxazine covalently linked to PDC, not to model TDP reactions. 17 The ratio of acetate to acetoin produced at pH 6 is 300.…”

“…1949, 71, 28. (17) Control experiments all at pH 6.0, ca. 22 °C, included the following: sodium pyruvate per se; sodium pyruvate with 1 mM 8-AcI or 6-AcI; sodium pyruvate with 1 mM 6-BrAcI or 1; sodium pyruvate with native PDC; sodium pyruvate with PDC and 1 mM 8-Acl or 1 mM 6-Acl.…”

Spectroscopic and structural features of small thiocarbonyl molecules in low‐lying excited states: Further applications of a variant of the orthogonal gradient method

“…Recently we have reported [2] a fairly successful series of calculations on the 'n+ states of a number of tetraatomic carbonyls (XYC = 0) in an INDO-MCSCF framework. This success encouraged us to extend these studies to a group of tetraatomic thiocarbonyls.…”