/*opinb add opacity of individual species, including stimulated emission */
void opinb(
  /* pointer to opacity offset with stack */
  long int ipOpac, 
  /* low energy limit to opacity bound */
  long int low, 
  /* high energy limit to opacity bound */
  long int ihi, 
  /* the abundance of the species in this level */
  float a, 
  /* the departure coefficient */
  double b,
  /* either 's' for static opacities, or 'v' for volitile */
  char chStat );