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_1_2_adas(Erel) result(sigma)
!+Calculates cross section for a proton-Hydrogen charge exchange interaction
!+from the \(n=1\) state to the \(m=2\) state at energy `Erel`
!+
!+###Equation
!+ $$H^+ + H(1) \rightarrow H(2) + H^+$$
!+###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 = [-4.036239511d3, 6.941235312d3, &
-5.186974866d3, 2.194885201d3, &
-5.765960509d2, 9.653534186d1, &
-1.008066138d1, 6.010731909d-1,&
-1.567417031d-2 ]
real(Float64) :: e, ee, fac, l, p
e = Erel*1.d3
if(e.ge.1.d3) then
ee = max(e,1.0)
fac = 1.d0
else
ee = 1.0d3
fac = Erel**(0.5)
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_1_2_adas