Hydrogen ground-state configuration

Thus, the UV spectrum of 22, was interpreted as incompatible with a a /a configuration. At the same time, the IR data were interpreted in favor of the a-ir/a-ir configuration. In addition, the reactivity pattern of 22 differs significantly from that of 6, which has a ground-state configuration. For example, 22 does not appear to ring expand upon irradiation (as 6 is known to do) and reacts with hydrocarbons (like methane) via hydrogen-atom abstraction (rather than by C—H insertion, as is the case with 6) [86,87]. Thus, the conclusion that 22 is a aTr/a-ir biradical was reached. 

Sonic examples of how these rules apply are showai in Table l.l. Hydrogen, for instance, has only one electron, which must occupy the lovvest-energ - orbital. Thus, hydrogen has a l.s ground-state configuration. Carbon has six electrons and the ground-state configuration Is 2s 2p. nd so forth. Note that a super-script is UbCd tn represent the number of electrons in a jiarticular orbital. 

In nonhydrogen bonding solvents, this molecule was shown to emit only at 500 nm. Emission at 390 nm could only be obtained in alcohols. These results demonstrate that the ultraviolet fluorescence component is due to molecules in which the carbonyl oxygen is not hydrogen bonded to the hydroxyl group. Equilibrium cannot be established between the two tautomers in the excited state only molecules which are in the correct ground state configuration will participate in a proton translocation. This proton translocation takes place in under 10 ps. Since neither a temperature dependence nor an isotope effect could be observed, the dynamic measurements do not elucidate the mechanism for the proton translocation. This question has been answered in part by the appUcation of laser-induced fluorescence. 

Note that since the hydrogenation is noncatalyzed, the reacting molecules have ground state configurations in accordance with (3) above. Also, according to (2), such reaction involves the overlap of the HOMO of one... 

There are two electrons to place in the MO energy-level scheme for LiH shown in Fig. 2-20. This total is arrived at by adding together the one valence electron contributed by hydrogen (Ir) and the one valence electron contributed by lithium (Ir). Both electrons are accommodated in the cr MO, giving a ground-state configuration... 

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