CNDO/S calculations

Molecular structures for CNDO/S calculations were optimized using HP/3-21G shown in Fig, 1, Dominant charge transfers at some selected states and their oscillator strength " /l(E-30 esu). 

The relative importance of the intrinsic (twist-related) and external contributions (e.g. stemming from the axial allylic groups) was evaluated for the first time by Rosenfield and Charney23 who carried out CNDO/S calculations on the model compounds 16-18. 

The magnetic circular dichroism spectrum of thioxanthone and the circular dichroism spectrum of its inclusion complex with cyclodextrin have been measured and interpreted with the aid of PPP and CNDO/S calculations. The first jtJt state exhibits intramolecular charge transfer characteristics <1994JPC10432>. 

The low-energy ionizations of 2-X, 3-X, 3,4-X2, 2,5-X2 and 2,3,4,5-X4 (X = Cl, Br, I) thiophen are correlated in Figures 24 a-c based on Hel/Hell ratio changes, band shape analyses, Penning ionization and CNDO/S calculations. The spectra of 3-phenyl-3-X-diazirines (X = Cl, Br or CF3) and 3,3-bis(trifluoromethyl)diazirine were studied by Kramarenko et al.m... 

Unsubstituted 5(6)-nitrobenzimidazole has two absorption bands in the field of 230-235 and 300-309 nm [1186, 1190-1192], Its long-wave band, as compared with the initial benzimidazole, is bathochromically moved by approximately 25 nm and does not show vibrational structure. The short-wave band, on the contrary, undergoes a hypsochromic shift (—10 nm) upon mononitration [709, 1193], Band displacement of this kind and the disappearance of vibrational observed for the long-wave band are responsible for essential differences in the localization and, hence, in the nature of, at least, one of the transitions. For example, from CNDO/S calculations it follows that the long-wave transition of benzimidazole is multicon-figurational (Table 3.70) and results in the total molecular excitement [1193],... 

FIGURE 5. Total net charges and 7c-electron densities (in parenthesis) from CNDO/S calculations for vinylamine, acrolein and 3-dimethylaminoacrolein. Experimental dipole moments are from References 17, 105 and 106, respectively... 

The energy states of unsubstituted triazene are not experimentally accessible because the hydride has not been isolated so far (cf. ref. 17). According to CNDO/S-calculations, the values are (50, 51) 14.41 (n ), 14.09 (ffi), 10.12 (/i-h), and 9.63 eV (n ). Because of the comparatively small energy difference between the n+- and ir2 molecular orbitals, the energy sequence of both these orbitals can reverse with appropriate choice of substituents on triazene (cf. Section II,B,1). 

Pulse radiolytic experiments with Cso in nitrogen-saturated or aerated DCE solutions yielded a doublet with maxima at 960 and 980 nm [64, 65]. This fingerprint is identical with that computed in CNDO/S calculations [66]. Because of the shortlived nature of the [DCE] + radical, the rate constants for the Ceo oxidation could only be estimated values were ca 2 x 10 m s [64, 65]. 

We have used semiempirical CNDO/S calculations for estimating the magnitude and nature of shifts accompanying the transition from a molecule to its vdW dimer. (Nj), (HF). HCl... HF, (H O) and (CO ) were studied. Qualitatively speaking, the results agree with those obtained by the ... 

FIGURE 25. Orbital diagram for lfI-l,3-benzazarsole according to CNDO/S calculations. Reproduced by permission of Elsevier Sequoia S.A... 

Experimental UV maxima jPjPjP calculation <70803344) CNDO/S calculation <74T2903>... 

The lowest energy absorption band is forbidden when the cubane has high symmetry but can be weakly allowed when it has low symmetry. Semiempirical CNDO/S calculation shows that the spectrum shape in the low energy region depends strongly on substituents (39). Among tert-... 

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