INFRARED ACTIVITY OF PEIERLS SYSTEMS AND APPLICATION TO POLYACETYLENE(REPRINTED FROM SOLID-STATE COMMUN, VOL 41, PG 729-734, 1982)

The conductivity of added charge (e.g. solitons) to a dimerized Peierl s condensate with N coupled phonon bands is considered. If the phonon frequencies are low compared with the Peierls gap and the charge exten ds over several atoms then: (a) The infra-red frequencies omega(n)phi( n = 1, 2,..., N) and their relative weights are independent of the cha rge configuration. (b) The product PI(n=1)N(omega(n)phi/omega(n)R), wh ere omega(n)R are the Raman frequencies, is isotope independent. The r esults are valid even if electron-electron interactions are present an d a pinning effect is included. The product rule (b) is in good agreem ent with data on trans (CH)x and (CD)x. This data also yields the coup ling constants and the pinning force.