      SUBROUTINE HZERO (PARTR, PARTI)
      IMPLICIT REAL*8 (A - H, O - Z)
      REAL*8 K2, IMZ12
      COMMON /AHZERO/ HZEROR,HZEROI
      D2 = PARTR**2 + PARTI**2
    8 K2 = .7978845608*EXP(PARTI)
      D = SQRT(D2)
      RLZ12 = (SQRT((PARTR + D)/2.))/D
      IF(D - PARTR) 9,9,10
    9 IMZ12 = 0
      GO TO 11
   10 IMZ12 = (SQRT((D - PARTR)/2.))/D
   11 COST = COS(PARTR)
      SINT =-SIN(PARTR)
      HZEROR = K2*(RLZ12*COST - IMZ12*SINT)
      HZEROI = K2*(IMZ12*COST + RLZ12*SINT)
      RETURN
      END
