Photoconductivity in trans (CH)x: A proof for the existence of solitons?

The optical absorption spectrum has been measured on trans (CH)_x upon simultaneous illumination of the sample with a second light source. No additional mid-gap absorption has been observed nor have the characteristic i.r. peaks been found which are known to show up at 0.11 and 0.17 eV upon doping. On the other hand photoconductivity has been detected, and, from its size, one would expect that the i.r. features should appear provided that the electron-hole pairs preferentially decay into soliton-antisoliton pairs, as predicted by theory. The negative results thus suggests that photo-generated carriers do not relax into solitonic states.