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_2_adas(Erel) result(sigma)
!+Calculates cross section for a proton-Hydrogen charge exchange interaction
!+from the \(n=3\) state to the \(m=2\) state at energy `Erel`
!+
!+###Equation
!+ $$H^+ + H(3) \rightarrow H(2) + H^+$$
!+###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(11), parameter :: a = [-1.149224555d6, 2.750368877d6, &
-2.942222842d6, 1.852584954d6, &
-7.603284323d5, 2.125284465d5, &
-4.097580431d4, 5.380901722d3, &
-4.606297192d2, 2.321345254d1, &
-5.230186707d-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 = 1.d16 * (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 + a(10)*l**9.0 + a(11)*l**10.d0
sigma = fac*(10.d0**p)
end function p_cx_3_2_adas