Some possibilities and limitations of the strictly localized model of molecular wave functions are discussed in the light of C N D 0 / 2 calculations. The analysis of non-orthogonal localized molecular orbitals obtained from usual SCF wavefunctions gives some insight into the effects omitted from the strictly localized model.Recently Barone et al.' applied a procedure giving self -consistent, strictly localized molecular orbitals. They separated approximately the C N D 0 / 2 or INDO Fock matrices into 2 x 2 blocks in a hybrid atomic basis. Independently of these authors we have performed similar calculations within the C N D 0 / 2 scheme, and the aim of the present Note is to point out some computational errors found in ref.(1) and, mainly, to supplement it with a brief summary of our results concerning related problems.A comparison of their results with ours, checked with great care, including hand calculations, shows that some (unreasonable) values quoted in ref.(1) (their method A) are erroneous. Table 1 demonstrates that the strictly localized model

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The 0 1s line of an ordinary, untreated glass surface and of a glass surface in its dealkalized state were studied by XPS. One single 0 1s peak was detected on tbe dealkalii sample at a bmding energy (BE) of 532.5 eV while on the alkalicontaining sample, and also on the dealkplized sample after alkali solution treatment, a second peak at 531.1 eV BE also could be detected. Experimental data were backed by semiempirical quantum cbemical cakulations. The observed low BE component of the 0 1s line, according to the outlined experimental evidence, is connected with the presence of alkali ions. This clearly contradicts earlier publications, interpreting the 0 1s line as originating from oxygen atoms in bridging and non-bridging positions.

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