30 lines
866 B
Fortran
30 lines
866 B
Fortran
SUBROUTINE DIVHE2(A,DIV)
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C ========================
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C
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C Auxiliary procedure for evaluating approximate Stark profile
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C for He II lines
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C This procedure is quite analogous to DIVSTR for hydrogen;
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C the only difference is a somewhat different definition
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C of the parameter A ,ie. A for He II is equal to A for hydrogen
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C minus ln(2)
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C
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INCLUDE 'PARAMS.FOR'
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PARAMETER (UN=1.,TWO=2.,UNQ=1.25,UNH=1.5,TWH=2.5,FO=4.,FI=5.)
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PARAMETER (CA=0.978,BL=5.821,AL=1.26,CX=0.28,DX=0.0001)
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C
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A=UNH*LOG(BETAD)-CA
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IF(BETAD.LT.BL) RETURN
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IF(A.GE.AL) THEN
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X=SQRT(A)*(UN+UNQ*LOG(A)/(FO*A-FI))
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ELSE
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X=SQRT(CX+A)
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ENDIF
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DO 10 I=1,5
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XN=X*(UN-(X*X-TWH*LOG(X)-A)/(TWO*X*X-TWH))
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IF(ABS(XN-X).LE.DX) GO TO 20
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X=XN
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10 CONTINUE
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20 DIV=X
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RETURN
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END
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