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m

[marquardt_constant !E]…

Allows for changing the Marquardt constants, the Simulated_Annealing_1 macro changes the Marquardt constants as follows:

load marquardt_constant { 0 1 }

[min_r #] [max_r #]

Defines the minimum and maximum radii for calculating bond lengths. min_r and max_r are by default set to 0 and 3.2 Å respectively.

[mixture_density_g_on_cm3 !E]

Calculates the density of the mixture assuming a packing density of 1, see also mixture_MAC.

[mixture_MAC !E]

Calculates the mass absorption coefficient in cm2/g for a mixture as follows:

where wi and (m/r)i is the weight percent and phase_MAC of phase i respectively. Errors are reported for phase_MAC and mixture_MAC.

The following example provides phase and mixture mass absorption coefficients.

xdd…

mixture_MAC 0

str…

phase_MAC 0

The macros Mixture_LAC_1_on_cm, Phase_LAC_1_on_cm and Phase_Density_g_on_cm3 calculates the mixture and phase linear absorption coefficients (for a packing density of 1) and phase density, for example:

xdd…

Mixture_LAC_1_on_cm(0)

str…

Phase_Density_g_on_cm3(0)

Phase_LAC_1_on_cm(0)

Errors for these quantities are also calculated. Mass absorption coefficients obtained from NIST at http://physics.nist.gov/PhysRefData/XrayMassCoef are used to calculate mixture_MAC and phase_MAC.


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