code: public static final Atom vectorProduct(Atom a , Atom b){
  
  		Atom c = new AtomImpl();
  		c.setX( a.getY() * b.getZ() - a.getZ() * b.getY() ) ;
  		c.setY( a.getZ() * b.getX() - a.getX() * b.getZ() ) ;
  		c.setZ( a.getX() * b.getY() - a.getY() * b.getX() ) ;
  		return c ;
  
  	}
docs: Vector product (cross product).
  
  @param a
  an Atom object
  @param b
  an Atom object
  @return an Atom object