Separation of carbon and nitrogen isotopes by selective photodissociation azo or diazo compounds

A method for the separation of isotopes by selective photodissociation of an organic nitrogen compound selected from an azo compound having the formula R.sub.1 N = NR.sub.2 wherein R.sub.1 and R.sub.2 represent the same or different organic radical and a diazoalkane having the linear structure R.sub.3 R.sub.4 C = N.sup.+ = N.sup.- wherein R.sub.3 and R.sub.4 are the same or different and are selected from hydrogen and an organic radical, said organic nitrogen compound containing an element in a plurality of isotopes, the optical absorption of molecules containing a first such isotope being spearated from the optical absorption of molecules containing a second isotope of the same element by an isotope shift, the method comprising:

• a. subjecting said organic nitrogen compound to radiation, at least a portion of said radiation being at a predetermined wavelength .lambda..sub.1 to selectively excite molecules containing the first isotope, said radiation having sufficient energy to dissociate the selectively excited molecules into molecular nitrogen and a radical product without substantially dissociating unexcited molecules, thereby producing a dissociation product enriched in the first isotope, and
• b. separating said dissociation product enriched in the first isotope from the reaction mixture.