\magnification=\magstep1


$$
U(x) \quad = \quad E \left( 10 \ - \ 5 e^{-(x/a)^2} \right)  \quad {\rm Joules}
$$

$$
n(\lambda) \quad = \quad \biggl[ 1 \ + \ 0.1 \left( {{300 \thinspace {\rm nm}}\over{\lambda}} \right) \biggr] 
$$

\bye
