SpectraRust/tlusty/extracted/gaunt.f
2026-03-19 14:05:33 +08:00

46 lines
1.6 KiB
Fortran

FUNCTION GAUNT(I,FR)
C ====================
C
C Hydrogenic bound-free Gaunt factor for the principal quantum
C number I and frequency FR
C
INCLUDE 'IMPLIC.FOR'
PARAMETER (UN=1.)
DIMENSION CGT(7,10),X(7),FRKW(10)
DATA CGT/0.,12.803223,-5.5759888,1.2302628,-2.9094219D-3,
* 7.3993579D-6,-8.7356966D-9,-2.0244141,2.1325684,-1.2709045,
* 1.1595421,-2.0735860D-3,2.7033384D-6,0.,-0.23387146,
* 0.52471924,-0.55936432,1.1450949,-1.9366592D-3,2.3572356D-6,
* 0.,-5.4418565D-2,0.19683564,-0.31190730,1.1306695,
* -1.3482273D-3,-4.6949424D-6,2.3548636D-8,-8.9182854D-3,
* 5.5545091D-2,-0.16051018,1.1190904,-1.0401085D-3,
* -6.9943488D-6,2.8496742D-8,-5.5303574D-3,4.1921183D-2,
* -0.13075417,1.1168376,-8.9466573D-4,-8.8393133D-6,
* 3.4696768D-8,-2.2752881D-3,2.3350812D-2,-9.5441161D-2,
* 1.1128632,-7.4833260D-4,-1.0244504D-5,3.8595771D-8,
* -9.7200274D-4,1.3298411D-2,-7.1010560D-2,1.1093137,
* -6.2619148D-4,-1.1342068D-5,4.1477731D-8,-4.9576163D-4,
* 8.5139736D-3,-5.6046560D-2,1.1078717,-5.4837392D-4,
* -1.2157943D-5,4.3796716D-8,-2.9467046D-4,6.1516856D-3,
* -4.7326370D-2,1.1052734,-4.4341570D-4,-1.3235905D-5,
* 4.7003140D-8/
DATA FRKW/6.6D15,9*3.3D15/
IF(I.LE.10) THEN
X(5)=FR/2.99793D14
X(6)=X(5)*X(5)
X(7)=X(6)*X(5)
X(4)=UN
X(3)=UN/X(5)
X(2)=X(3)*X(3)
X(1)=X(2)*X(3)
GAUNT=0.
DO 10 J=1,7
GAUNT=GAUNT+CGT(J,I)*X(J)
10 CONTINUE
ELSE
GAUNT=UN
ENDIF
RETURN
END