ADAS Subroutine qvain
FUNCTION QVAIN(Z1,N1,N2,VION,PHI,ZP) C IMPLICIT REAL*8(A-H,O-Z) C C----------------------------------------------------------------------- C C ****************** FORTRAN77 FUNCTION: QVAIN ************************ C C PURPOSE: CALCULATES ION COLLISION CROSS-SECTIONS FOR TRANSITIONS C BETWEEN PRINCIPAL QUANTUM SHELLS IN HYDROGEN AND C HYDROGENIC IONS. C C INPUT C Z1 = TARGET ION CHARGE +1 C N1 = INITIAL PRINCIPAL QUANTUM NUMBER C N2 = FINAL PRINCIPAL QUANTUM NUMBER C VION = VELOCITY OF INCIDENT ION (CM/SEC) C ZP = PROJECTILE CHARGE C OUTPUT C QVAIN=CROSS-SECTION IN PI*A0**2 UNITS C C NOTES: THIS ROUTINE IS NOT YET PROPERLY ANNOTATED C C UNIX-IDL PORT: C C VERSION: 1.1 DATE: 16-1-96 C MODIFIED: TIM HAMMOND (TESSELLA SUPPORT SERVICES PLC) C - FIRST VERSION C C VERSION: 1.2 DATE: 16-05-07 C MODIFIED: Allan Whiteford C - Updated comments as part of subroutine documentation C procedure. C----------------------------------------------------------------------- C ZZ1=Z1*Z1 ZZP=ZP*ZP EN1=N1 EN2=N2 EIJRH=DABS(1/(EN1*EN1) - 1/(EN2*EN2)) ALFA=1.0/137.036 CLIG=2.998D+10 CFAC=(CLIG/VION)**2 BETA=0.5*ALFA*ALFA*CFAC*DSQRT(PHI)*EIJRH*ZP XFAC1=2*ALFA*ALFA*CFAC*PHI*ZP*ZP QVAIN=XFAC1*DEXP(-2*DSQRT(BETA))*RIFAC(BETA) RETURN END C FUNCTION RIFAC(BETAIN) IMPLICIT REAL*8(A-H,O-Z) INTEGER N1, N2 REAL*8 PHI, VION, Z1, ZP REAL*8 BETAIN