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m [2009/08/06 15:39]
clare created
m [2009/08/27 12:16] (current)
clare
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 ====== m ====== ====== 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 //​[[#​k038|mixture_MAC]]////​.//​
 +
 +**[//​mixture_MAC//​ !E]**
 +
 +Calculates the mass absorption coefficient in cm<​sup>​2</​sup>/​g for a mixture as follows:
 +
 +<​sub>​{{techref_files:​image160.gif?​160x45}}</​sub>​where //​w//<​sub>​i</​sub>​ and (//​m/////​r//​)<​sub>​i</​sub>​ 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|http://​physics.nist.gov/​]][[http://​physics.nist.gov/​PhysRefData/​XrayMassCoef|P]][[http://​physics.nist.gov/​PhysRefData/​XrayMassCoef|hysRefData/​XrayMassCoef]] are used to calculate //​mixture_MAC//​ and //​phase_MAC//​.
  

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