R. K. Kothari

Electron momentum density distribution in Cd3P2

Abstract A study of electron momentum density distribution in Cd 3 P 2 is reported in this work. The measurement of Compton profile is carried out on a polycrystalline sample using 59.54 keV gamma-rays emanating from an 241 Am radioisotope. The theoretical calculations are performed using linear combination of atomic orbitals method following the Hartree–Fock and a posteriori density functional theories. The spherically averaged theoretical Compton profiles are in good agreement with the measurement. The best agreement is, however, shown by the Hartree–Fock scheme. Simple ionic model calculations for a number of configurations ( Cd + x ) 3 ( P − 3 x / 2 ) 2 ( 0.0 ⩽ x ⩽ 2.0 in step of 0.2) are also performed utilizing free atom profiles. The ionic model supports transfer of 2.0 electrons per Cd atom from 5 s state to 3 p state of P.

Bremsstrahlung contribution in Compton scattering from heavy metals

Abstract Theoretical estimates of the spectral distribution and total intensity of the bremsstrahlung (BS) relative to the Compton yield have been determined for photoelectrons liberated in scattering experiments on heavy metals with 60 keV radiation. Whereas the total-intensity calculations are based on the approach of Alexandropoulos et al., the spectral distribution has been computed using the Born approximation along with the Elwert and form factor corrections. These results are compared with another calculation based on the approach of Lee et al. Typical results for Mo, Ta, and W are presented. It is found that the relative contribution of BS from a W target is not trivially small, although K-shell photo-ionisation is not possible at these energies.

Electronic Properties of ZnO: Band Structure and Directional Compton Profiles

The electronic band structure and directional Compton profiles (DCPs) of ZnO are studied in this work. Calculations are performed considering a set of three schemes based on density functional theory (DFT), the Hartree–Fock (HF) method, and a hybrid scheme. All band structures predict direct bandgaps. The best agreement with experiment is, however, shown by the hybrid scheme. The three schemes are also applied to compute DCPs along [100], [110], and [001] directions. These are compared with measurements made on single crystals of ZnO employing a 59.54 keV gamma-ray Compton spectrometer. Calculations overestimate the momentum density in the low-momentum region while underestimate the anisotropies. Positions of extremes in anisotropies deduced from calculations are well reproduced by the measured anisotropies in some cases. Within the experimental limits, the DCPs from the HF method are in better agreement with the measurements compared with DFT.

Compton profile study of polycrystalline ZnBr2

The first ever Compton profile study of polycrystalline ZnBr2 is presented in this paper. The measurement of polycrystalline sample of ZnBr2 is performed using 59.54 keV gamma‐rays emanating from an 241Am radioisotope. Theoretical calculations are performed following the Ionic model calculations for a number of configurations Zn+xBr2−x/2 (0.0≤x≤2.0 in step of 0.5) utilizing free atom profiles. The ionic model suggest transfer of 2.0 electrons from 4 s state of Zn to 4 p state of two Br atoms. The autocorrelation function B(z) is also derived from experiment and the most favoured ionic valence Compton profiles.