CALCULATIONS OF
ELECTRON ATOMIC SCATTERING FACTORS AND TEMPERATURE DEPENDENT DEBYE-WALLER
FACTORS
Department of
Electronics, Peking University, Beijing 100871, China (plm@ele.pku.edu.cn)
Electron atomic scattering factors and
Debye-Waller factors are two types of important parameters that an electron
crystallographer must have before conducting any quantitative electron
crystallography work. While numerical values of electron atomic scattering
factors are available for all free neutral atoms and most commonly occurring
ions[1], Debye-Waller factors are more difficult to find and most of the time
the existing Debye-Waller factors are given only at few fixed temperatures and
it is not always clear as to how to interpolate these values to other
temperatures. In this lecture we will be concerned with the advantages of using
an alternative analytical expression [2] for the electron atomic scattering
factors, especially those for ions and for reflection high-energy electron
diffraction (HREED) and surface calculations [3-5]. We will also present
results on lattice dynamics calculations on a range of compounds, especially
oxides, and the evaluation of temperature dependent Debye-Waller factors from
these calculations, their parameterization [6-8] and computation of absorptive
scattering factors of electrons [9].
References
1
J.M. Cowley
(1999) International Tables for Crystallography, Volume C, p259, Kluwer Academic Publishers
2
J.M. Cowley,
L.-M. Peng, G. Ren, S.L. Dudarev and M.J. Whelan (1999) International Tables
for Crystallography,
Volume C, p262 (1999) Kluwer Academic Publishers
3
L.-M. Peng,
G. Ren, S.L. Dudarev and M.J. Whelan (1996) Acta Cryst. A52, 257
4
L.-M. Peng,
S.L. Dudarev and M.J. Whelan (1998) Phys. Rev. B57, 7259
5
L.-M. Peng
(1998) Acta Cryst. A54, 481
6
H.X. Gao,
L.-M. Peng and J.M. Zuo (1999) Acta Cryst. A55,1014
7
H.X. Gao and
L.-M. Peng (1999) Acta Cryst. A55, 926
8
H.X. Gao and
L.-M. Peng (2000) Acta Cryst. A56, 519
9
L.-M. Peng,
G. Ren, S.L. Dudarev and M.J. Whelan (1996) Acta Cryst. A52, 456