Fit Function
Details |
\[\begin{align*}
\sigma (pe) &= \text{pcf(1)} \left( c_1 + c_2 + c_3 \right) \\
\text{where} \quad c_1 &= \begin{cases}
\exp\left(-\frac{\text{pcf(2)}}{pe}\right) \cdot \frac{\log\left(1 + \text{pcf(3)} \cdot pe\right)}{pe}, & \text{if } \left|\frac{\text{pcf(2)}}{pe}\right| < 700 \\
0, & \text{otherwise}
\end{cases} \\
c_2 &=
\begin{cases}
\frac{\text{pcf(4)} \cdot \exp\left(-\text{pcf(5)} \cdot pe\right)}{pe^{\text{pcf(6)}}}, & \text{if } \left|\text{pcf(5)} \cdot pe\right| < 700 \\
0, & \text{otherwise}
\end{cases} \\
c_3 &=
\begin{cases}
\frac{\text{pcf(7)} \cdot \exp\left(-\frac{\text{pcf(8)}}{pe}\right)}{1 + \text{pcf(9)} \cdot pe^{\text{pcf(10)}}}, & \text{if } \left|\frac{\text{pcf(8)}}{pe}\right| < 700 \\
0, & \text{otherwise}
\end{cases}
\end{align*}\] |
| Python |
def hexc2(pe, pcf):
"""
This function calculates the cross-section for heavy particle collisions.
pe: collision energy in keV/amu
pcf: parameter data array
pcf[0:10]: parameters for fit to the cross section
"""
dexpr = 700.0
arg1 = -pcf[1]/pe
c1 = np.where(np.abs(arg1) < dexpr, np.exp(arg1) * np.log(1 + pcf[2] * pe)/e, 0.0)
arg2 = -pcf[4] * pe
c2 = np.where(np.abs(arg2) < dexpr, pcf[3] * np.exp(arg2)/(pe**pcf[5]), 0.0)
arg3 = -pcf[7]/pe
c3 = np.where(np.abs(arg3) < dexpr, pcf[6] * np.exp(arg3)
/ (1 + pcf[8] * (pe**pcf[9])), 0.0)
pxs = pcf[0] * (c1 + c2 + c3)
return pxs |
| Fortran |
c
c###################################################################
c
subroutine hexc2(pe, pcf, kncf, pxs, kermsg)
c
c this is a subroutine to calculate cross sections (cm[2])
c versus projectile energy (ev) for heavy particle collisions.
c
c pe = collision energy in kev/amu
c
c pcf(1-10) = parameters for fit to the cross section
c
c kermsg = blank if no errors
c
c pxs = cross section in 10e-16 cm[2]
c------------------------------------------------------------------------
c
double precision pe, pcf, pxs
double precision e, a1, a2, a3, a4, a5, a6, arg1, arg2, arg3
double precision a7, a8, a9, a10, c1, c2, c3, dexpr, zero, one
c
dimension pcf(10)
character*(*) kermsg
data dexpr/7.00d+02/
data zero/0.00d+00/
data one/1.00d+00/
c
c generate e, the energy in kev
c
e = pe
a1= pcf(1)
a2= pcf(2)
a3= pcf(3)
a4= pcf(4)
a5= pcf(5)
a6= pcf(6)
a7= pcf(7)
a8= pcf(8)
a9= pcf(9)
a10= pcf(10)
arg1=-a2/e
c1=zero
if (dabs(arg1) .lt. dexpr) c1=dexp(arg1) * dlog(one+(a3*e))/e
c
arg2=-a5*e
c2=zero
if (dabs(arg2) .lt. dexpr) c2=a4*dexp(arg2)/(e**a6)
c
arg3=-a8/e
c3=zero
if (dabs(arg3) .lt. dexpr) c3= a7*dexp(arg3)/
1 (one + a9*(e**a10))
c
pxs=a1*(c1 + c2 + c3)
return
end |