TEMPERATURE-DEPENDENCE OF THE NA-N(-RESPONSE() OPTICAL)

Photoabsorption cross sections were measured for Na-n(+) , n=9, 21, an d 41 at two temperatures, a low one at T approximate to 130 K, and a h igh one with T>300 K. A large, unexpected temperature effect is observ ed. The single, broad peaks observed at high temperature become narrow er at 130 K for n=21 and 41. For Na-g(+) a splitting into two peaks se parated by 275 meV is observed. For n=21 and 41 a temperature dependen t shoulder appears on the blue side of the main absorption.