function epsln(tmp,dna,a10,p10,rdmol,rmcol)
        implicit double precision (a-h,o-z)
	parameter (pi=3.1415926d0,rkb=1.3806d-16,eight=8.d0)
C       -----------------------------------------------
C          Calculate V-T proability from Landau-Teller
C          Formula
C       -----------------------------------------------
cd        t3 = tmp**0.333333333333d0
cd	p10 = p0(ib)*dexp(-ap(ib)/t3)
        z10 = (rdmol**2)*dsqrt(eight*pi*rkb*tmp/rmcol)
	c10 = p10*z10*dna
	epsln = c10/a10

	return
	end