The dissociation energy of MgO

The low-lying electronic states of MgO

The low-lying singlet and triplet states of MgO have been studied using a SA-CASCF/IC-MRCI approach using the aug-cc-pV5Z basis set. The spectroscopic constants (r e , w e , and T e ) are in good agreement with the available experimental data. The computed lifetime for the B state is in excellent agreement with two of the three experimental results. The d state lifetime is in good agreement with experiment, while the computed D state lifetime is about twice as long as experiment.

Cluster Model Theoretical Study of the Interaction and Penetration of F on a Si Surface

The interaction of fluorine with a three-fold open site of the Si(111) surface has been examined using a cluster model. The site considered is taken as representative of one where penetration of the surface may occur. New analyses are used to show that the interaction is ionic with F having essentially a full negative charge for all distances near the surface, both above and below. The bonding is shown to be almost entirely electrostatic between the polarized charges of the positive Si surface and F-. The F-Si binding energy is estimated taking proper account of the electron affinity of F and the ionization potential, work function, of Si. When this is done, it is shown that there is no barrier for the penetration of the Si surface by F; hence, this penetration should not be a rate limiting step in the F-Si etching reaction.