Lithium ion clusters Li n + with n ranging up to 19 have been observed from liquid lithium ion sources by using a magnetic mass analyzer. The ion intensity as a function of cluster size showed local maxima at n=7, 9, 13, and 19. Only n=9 and 19 can be explained by the electronic shell model, which successfully predicts magic numbers of other alkali metal (Na, K) clusters. On the other hand, the geometrical atom packing model explains the observed magic numbers except for n=9.

No abstract

No abstract

No abstract

The contribution of substituent groups to the extractability of phenols and benzoic acids was examined by using a substituent constant, n, derived from the distribution coefficients of nonionic substances. This constant is defined as nx=log KD(x)-log KD(H), where KD(x) is the distribution coefficient of a derivative and log KD(H) is that of the parent compound. The substituent constants of the groups at the ortho-position of phenol were found to vary with a variation of the extraction solvent, possibly due to competition between the hydration and solvation of an organic solvent. From the KD values of the phenols and benzoic acids determined between chloroform and water, the substituent constants of halogeno, cyano, trifluoromethyl and nitro groups were calculated. In phenols, the m values of the ortho-substituting group (ic°) were greater than those of the mew-and para-substituting group, irm and np, respectively, whereas in benzoic acids i° are smaller than xm and np. Such results can be explained by a masking effect and the overlapping effect: the masking effect increases the n° values, whereas the overlapping effect decreases the n° values. A method for predicting the total n values of di-and tri-substituted phenols and benzoic acids is proposed.