subroutine drfdbo(jdn,xmol,t,TSTAR,DBSTAR, 
     &        sig,epsm,delm,chim)  
C ** return to reduced temperature and deBoer parameter         ** 
C **        for a given temperature                             ** 
C                                                               ** 
C                     SNL / phpaul Oct/1997 all rights reserved ** 
C                     last modified Oct/15/97                   ** 
C **************************************************************** 
C inputs: 
C       JDN - id number of species 
C      XMOL - NS long vector containing molecular weights 
C         T - temperature (K) 
C       *** - set of molecular parameter arrays from DRINIT 
C returns for temperature TMIN and species #jdn: 
C     TSTAR - reduced temperature  (dimensionless) 
C    DBSTAR - rediced deBoer parameter (dimensionless) 
C ****************************************************************       

      IMPLICIT NONE
      include 'drfmcm.for' 

      integer jdn
      double precision zz, eps, tstar, t, dbstar, dboer

C passed arrays 
      real*8 sig(KD),epsm(KD,KD),delm(KD,KD),chim(KD,KD),xmol(KD) 
C internal working arrays (none)  
      DATA dboer /43.761D0/ 


C  DBOER = scaling for reduced DeBoer parameter        
      zz = 1.d0 + chim(jdn,jdn) + delm(jdn,jdn)/t 
      eps = epsm(jdn,jdn)*zz*zz  
      tstar = t/eps 
      dbstar = dboer/(sig(jdn)*dsqrt(xmol(jdn)*eps))       
      return 
      end