K. B. Joshi

Compton profile study of bonding in BeO

The isotropic Compton profile of BeO has been measured using a γ-ray Compton spectrometer which employs a 5 Ci annular 241Am source. The measurement is compared with the theoretical HF-LCAO Compton profile published by Lichanot et al. The measurement has also been compared with our calculations based on the RFA model employing different ionic wavefunctions. It is seen that the experimental Compton profile is in very good agreement with the HF-LCAO calculations. To determine the nature of bonding, equal-valence-electron-density Compton profile of BeO has been compared with that of the isovalent compound MgO. It is observed that the bonding in BeO is partially covalent and less ionic than MgO in agreement with the conclusions of the HF-LCAO calculation.

Electronic Structure of Platinum: A Compton Profile Analysis

In this paper we report the results of a Compton profile study on polycrystalline platinum. The measurement has been made using 241 Am γ-rays and is compared with APW calculations of Papanicolaou et al. and also with our calculations based on the renormalized-free-atom (RFA) model. It is seen that the incorporation of electron correlation effects improves slightly the agreement between APW theory and experiment but the best fit to our experimental data is seen for the simple RFA model for 5d 9.2 6S 0.8 configuration. A comparison of the equal valence-electron-density Compton profiles of platinum and the other two isogroup metals, namely palladium and nickel, reveals an interesting trend for the d-band width in agTeement with the results based on photoemission measurements. The d-band occupancy as determined from RFA analysis is in agreement with Lytles estimates.

Electron momentum density distribution in iridium by Compton scattering technique

The isotropic Compton profile of iridium, measured using 59.54 keVγ-rays, is reported in this paper. The results are compared with the theoretical Compton profiles from APW method with and without incorporating electron correlation effects. It is seen that correlation effects improve the agreement between the experiment and theory. Comparison with the renormalized-free-atom (RFA) model calculations has also been made. Behaviour ofd-band electrons in Ir and some other 5d transition metals is discussed in terms of broadening in their Compton profiles.