Calculates cross section for a proton-Hydrogen charge exchange interaction
from the state to the state at energy Erel
Type | Intent | Optional | Attributes | Name | ||
---|---|---|---|---|---|---|
real(kind=Float64), | intent(in) | :: | Erel | Relative collision energy [keV/amu] |
Cross Section []
function p_cx_3_4_adas(Erel) result(sigma)
!+Calculates cross section for a proton-Hydrogen charge exchange interaction
!+from the \(n=3\) state to the \(m=4\) state at energy `Erel`
!+
!+###Equation
!+ $$H^+ + H(3) \rightarrow H(4) + H^+$$
!+###References
!+* Ref. 4 [[atomic_tables(module)]]
real(Float64), intent(in) :: Erel
!+ Relative collision energy [keV/amu]
real(Float64) :: sigma
!+ Cross Section [\(cm^2\)]
real(Float64), dimension(9), parameter :: a = [ 1.705303425d4,-3.316878090d4, &
2.792556433d4,-1.330264490d4, &
3.921666688d3,-7.327555138d2, &
8.476342861d1,-5.551987930d0, &
1.577120745d-1 ]
real(Float64), parameter :: n = 3.0
real(Float64) :: ee, fac, l, p
if(Erel.lt.90.0) then
ee = max(Erel * 1.d3 * n**2.0, 1.d3) !keV to eV
fac = 1.d0
else
ee = 90.0 * 1.d3 * n**2.0
fac = 0.82d16 *(Erel*n**2.0)**(-5.5)
endif
l = log10(ee)
p = a(1) + a(2)*l + a(3)*l**2.0 + a(4)*l**3.0 + &
a(5)*l**4.0 + a(6)*l**5.0 + a(7)*l**6.0 + &
a(8)*l**7.0 + a(9)*l**8.0
sigma = fac*(10.d0**p)
end function p_cx_3_4_adas