26 lines
616 B
Fortran
26 lines
616 B
Fortran
FUNCTION CEH12(T)
|
|
C =================
|
|
C
|
|
C Special formula for collisional rate in hydrogen Lyman-alpha
|
|
C transition
|
|
C After Crandall et al. Ap.J. 191, 789 (1974)
|
|
C
|
|
INCLUDE 'IMPLIC.FOR'
|
|
DIMENSION A(6),B(8)
|
|
PARAMETER (C=-118353.41)
|
|
DATA A/ 2.579997D-10, -1.629166D-10, 7.713069D-11,
|
|
* -2.668768D-11, 6.642513D-12, -9.422885D-13/
|
|
SAVE A
|
|
c
|
|
DO I=1,8
|
|
B(I)=0.
|
|
END DO
|
|
X=LOG10(T)-4.
|
|
DO I=1,6
|
|
J=7-I
|
|
B(J)=2.*X*B(J+1)-B(J+2)+A(J)
|
|
END DO
|
|
CEH12=2.4*SQRT(T)*(B(1)-B(3))*EXP(C/T)
|
|
RETURN
|
|
END
|