Knowledge Bank

We analysed tabulated data for neutral and ionized diatomic molecules: thermodynamic properties, ionicity, condensation point, 16 spectroscopic/collision properties and for 6 of them $(\Delta prop,/\Delta ioniz.)\theta constantnC$ and for 4 of these (d prop./d ioniz.) $\theta constantnC.1$ These data firstly support a periodic system of diatomic molecules (PSDM) which initially assumes the two atoms to have weak $interaction.2$ The PSDM is constructed in 4-space by direct product of the periodic chart of the atoms (PCA), a matrix, with $itself.3$ Visualizable 3-d projections will be shown. This construction suggests that properties common to atoms and to molecules should be multiplicative or additive. Some properties are, e.g. number of electrons (!), radit and $re$ (poorly), and (d IP/d ioniz.) $\theta constantne,4$ The data secondly support refinements of the PSDM based on group theory, which turn rests on a preferred form of the $PCA.5$ Diatomics have been classified according to isoelectronic series and to extent of heteronuclearicity by means of operators compatible with the group. The construction based on the direct product, and the transformation to isoelectronic and heteronuclear coordinates, are being generalized to n-atomic molecules. An algorithm exists for mapping ionized diatomic molecules onto the coordinate frame of the PSDM. Least-squares fitting of data for neutral (with, if desired, ionized) molecules to simple functions of from one to four coordinates has begun and some $re$ have $predicted.2$