Vertical spectrum of ethene: uncontracted versus contracted correlation methods and the role of the adapted molecular orbitals

Abstract Ethylene vertical excitation energies (VEE) below 9.5 eV have been calculated with the complete active-space singles and doubles configuration interaction self-consistent size-consistent dressing (SC) 2 CAS–SDCI. The mean of the absolute deviation from experiment for the calculated VEE are 0.14, 0.05 and 0.03 eV for three different molecular orbital (MO) sets tried. The results show that an uncontracted method and a realistic MO set avoid the difficulties present in the calculation of the strongly mixed Rydberg-valence 1B 1u states.

Ab Initio Study on the Mechanism of Tropospheric Reactions of the Nitrate Radical with Haloalkenes:  Chloroethene

Ab Initio Study on the Mechanism of the Reactions of the Nitrate Radical with Haloalkenes:  1,2-Dichloroethene, 1,1-Dichloroethene, Trichloroethene, and Tetrachloroethene

A general mechanism for the reactions of the NO3 radical with 1,2-dichloroethene, 1,1-dichloroethene, trichloroethene, and tetrachloroethene is proposed from ab initio DFT calculations. The calculated mechanism shows three main parallel reaction pathways. For the systems where the two carbon atoms are differently substituted, the study includes both the attacks with Markownikoff and contra-Markownikoff orientation. The first reaction pathway leads to the formation of an epoxide along with the NO2 radical, the second one to the formation of carbonyl compounds, and the third one leads, through the cleavage of the C−C bond, to the formation of carbonyl compounds with a lower number of carbon a…

Ab Initio Study on the Mechanism of Tropospheric Reactions of the Nitrate Radical with Alkenes:  Propene

DFT Theoretical Study on the Reaction Mechanism of the Nitrate Radical with Alkenes:  2-Butene, Isobutene, 2-Methyl-2-butene, and 2,3-Dimethyl-2-butene

A general mechanism for the reactions of the NO3 radical with 2-butene, isobutene, 2-methyl-2-butene, and 2,3-dimethyl-2-butene is proposed on the basis of density functional theory (DFT) calculati...