Key points are not available for this paper at this time.
The spec tral d istribu t ions of t he H -a nd 0-cross sectio ns fo r photodeta chmen t ha ve bee n meas ured. The H -meas m ements are co ns isten t wi th t he t heor y of Chandrasekhar. A c ur v~ has been fi tted to t he res ul ts for 0 -. The t hres ho ld of this cross section, t he a ffi nity of 0 -, IS found to be l. 48 0.10 electron volts . No evidence is fo und f or reso na nce a t t he t hres hold 01' for t he ex iste nce of excited 0 -ions . The apparatus is described in d etail.
Smith et al. (1955) studied this question.