# CXRO Henke Files, downloaded on the 30.09.2025 from:
# https://henke.lbl.gov/optical_constants/asf.html
#
# 		Low-Energy X-ray Interaction Coefficients:
# 		Photoabsorption, Scattering, and Reflection
# 			E = 30-30,000 eV, Z = 1-92
#
# 	        B. L. Henke, E. M. Gullikson, and J. C. Davis
# 			Center for X-Ray Optics, 2-400
# 			Lawrence Berkeley Laboratory
# 			Berkeley, California 94720
#
# These files were used to generate the tables published in reference [1].
# The files contain three columns of data: Energy(eV), f_1, f_2,
# where f_1 and f_2 are the atomic (forward) scattering factors.
# There are 500+ points on a uniform logarithmic mesh with points
# added 0.1 eV above and below "sharp" absorption edges.
# (Note: below 29 eV f_1 is set equal to -9999.)
# The tabulated values of f_1 contain a relativistic, energy independent,
# correction given by, Z* = Z - (Z/82.5)^(2.37).
#
# The atomic photoabsorption cross section, mu_a, may be readily obtained
# from the values of f_2 using the relation,
#
# 			mu_a = 2*r_0*lambda*f_2
#
# where r_0 is the classical electron radius, and lambda is the wavelength.
# The index of refraction for a material with N atoms per unit volume
# is calculated by,
#
# 		n = 1 - N*r_0*(lambda)^2*(f_1+if_2)/(2*pi).
#
# These (semi-empirical) atomic scattering factors are based upon
# photoabsorption measurements of elements in their elemental state.
# The basic assumption is that condensed matter may be modeled as a
# collection of non-interacting atoms.  This assumption is in general
# a good one for energies sufficiently far from absorption thresholds.
# In the threshold regions, the specific chemical state is important
# and direct experimental measurements must be made.
#
# These tables are based on a compilation of the available experimental
# measurements and theoretical calculations.  For many elements there is
# little or no published data and in such cases it was necessary to
# rely on theoretical calculations and interpolations across Z.
# In order to improve the accuracy in the future considerably more
# experimental measurements are needed.
#
# Please send any comments to EMGullikson@lbl.gov.
#
# Note that the following elements have been updated since the publication
# of Ref. [1] in July 1993.
#
# Element		Updated		Energy Range
# Mg		1/15/94		30-50 eV
# Al		1/15/94		30-73 eV
# Si		1/15/94		30-100 eV
# Au		11/7/94		2000-6500 eV
# Li		11/15/94	2000-30000 eV
#
# [1]  B. L. Henke, E. M. Gullikson, and J. C. Davis,
# Atomic Data and Nuclear Data Tables Vol. 54 No. 2 (July 1993).
#
