ADAS Subroutine qbchid
FUNCTION QBCHID(Z,XI,ZETA,ENER) IMPLICIT REAL*8(A-H,O-Z) C----------------------------------------------------------------------- C C ********************* FORTRAN77 SUBROUTINE QBCHID ******************* C C PURPOSE: C EVALUATES A SHELL CONTRIBUTION TO THE IONISATION RATE COEFFICIENT C IN THE BURGESS-CHIDICHIMO APPROXIMATION MNRAS(1983)203,1269. C EXCLUDING THE THRESHOLD CORRECTION FACTOR C C CALLING PROGRAM: C SPFMAN11.FOR C C INPUT: C Z=TARGET ION CHARGE NUMBER C XI=EFFECTIVE IONISATION POTENTIAL FOR SHELL (RYD) C ZETA=EFFECTIVE NUMBER OF EQUIVALENT ELECTRONS IN SHELL C ENER=ELECTRON ENERGY (RYD) C C OUTPUT: C QBCHID=IONISATION CROSS-SECTION (PI*A0**2) C C AUTHOR: C H.P SUMMERS, JET 1 JULY 1987 C C UNIX-IDL CONVERSION: C C VERSION 1.1 DATE: 29-08-96 C MODIFIED: WILLIAM OSBORN, TESSELLA SUPPORT SERVICES PLC. C - NO FUNCTIONAL CHANGES TO IBM VERSION. C C----------------------------------------------------------------------- QBCHID=0.0D0 IF(ENER.LE.XI)RETURN C=2.3D0 BETA=0.25D0*(DSQRT((100.0D0*Z+91.0)/(4.0D0*Z+3.0D0))-5.0D0) T1=ZETA*DLOG(ENER/XI)/(XI*ENER) W=(DLOG(ENER/XI))**(BETA*XI/ENER) C OMIT THE W THRESHOLD ADJUSTMENT C QBCHID=C*T1*W QBCHID=C*T1 10 RETURN END REAL*8 ENER, XI, Z, ZETA