Aq_excit_n Function

function Aq_excit_n(eb, q, n, m_max) result(sigma)
    !+Calculates an array of the excitation cross sections for a neutral Hydrogen atom transitioning from
    !+the `n` state to the m=1..`m_max` states due to a collision an ion with charge `q` at energy `eb`
    !+
    !+@note Uses specialized cross sections if available else uses generic cross sections
    !+
    !+###Equation
    !+$$ A^{q+} + H(n) \rightarrow A^{q+} + H(m=1..m_{max}), q \gt 3, m \gt n, n \gt 3 $$
    !+
    !+###References
    !+* Page 132 in Ref. 5 [[atomic_tables(module)]]
    !+* Page 134 in Ref. 5 [[atomic_tables(module)]]
    !+* Page 136 in Ref. 5 [[atomic_tables(module)]]
    !+* Page 138 in Ref. 5 [[atomic_tables(module)]]
    !+* Page 140 in Ref. 5 [[atomic_tables(module)]]
    !+* Page 142 in Ref. 5 [[atomic_tables(module)]]
    !+* Page 142 in Ref. 5 [[atomic_tables(module)]]
    !+* Page 144 in Ref. 5 [[atomic_tables(module)]]
    !+* Page 146 in Ref. 5 [[atomic_tables(module)]]
    !+
    real(Float64), intent(in)       :: eb
        !+ Collision energy [keV]
    integer, intent(in)             :: q
        !+ Ion charge
    integer, intent(in)             :: n
        !+ Initial atomic energy level/state
    integer, intent(in)             :: m_max
        !+ Number of m states to calculate
    real(Float64), dimension(m_max) :: sigma
        !+ Array of cross sections where the m'th index refers to
        !+an excitation from the `n` state to the m'th state [\(cm^2\)]

    select case (n)
        case (0)
            stop
        case (1)
            sigma = Aq_excit_1_janev(eb, q, m_max)
        case (2)
            sigma = Aq_excit_2_janev(eb, q, m_max)
        case (3)
            sigma = Aq_excit_3_janev(eb, q, m_max)
        case DEFAULT
            sigma = Aq_excit_n_janev(eb, q, n, m_max)
    end select

end function Aq_excit_n