Annotation of OpenXM_contrib/gnuplot/demo/reflect.fnc, Revision 1.1
1.1 ! maekawa 1: #
! 2: # Model function for Reflectivity evaluation
! 3: #
! 4:
! 5: mu = 1.130469005513490E-001 # (cm-1) @ 17.479 keV
! 6: t0 = 0.18 # cm
! 7: tb = 11.417823202820120 * 0.01745329251994 # thetaB (radians)
! 8: A = mu * t0 / cos(tb)
! 9: P = (1 + (cos(2.*tb))**2) / 2
! 10: Fhkl = sqrt(3.536346308456155**2 + (4.58815426260982e-4)**2) * 0.968
! 11: r0 = 2.81794092e-13 # classical electron radius
! 12: lambda = 7.09338062818239e-9 # Mo K in cm
! 13: V = 1.62253546981499e-23
! 14: P = (1. + (cos(2.*tb))**2) / 2.
! 15: #
! 16: # combine constants to avoid exponential overflow on systems with
! 17: # D floating point format where exponential limits are ca. 10**(+/-38)
! 18: # r0liV = r0 * lambda / V
! 19: r0liV = 2.81794092*7.09338062818239/1.62253546981499e-1
! 20: #
! 21:
! 22: W(x) = 1./(sqrt(2.*pi)*eta) * exp( -1. * x**2 / (2.*eta**2) )
! 23: Y(tc) = tc/sin(tb) * Fhkl * r0liV
! 24: f(tc)= (tanh(Y(tc)) + abs(cos(2.*tb)) * tanh(abs(Y(tc)*cos(2.*tb)))) / (Y(tc)*(1.+(cos(2.*tb))**2))
! 25: Q(tc) = (r0*Fhkl/V)**2 * (lambda**3/sin(2.*tb)) * P * f(tc)
! 26: a(x) = W(x) * Q(tc) / mu
! 27:
! 28: #
! 29:
! 30: R(x) = sinh(A*a(x)) * exp(-1.*A*(1.+a(x)))
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