Аннотация:A method, suggested by us earlier for identification of materials with close spectra in terahertz range of frequencies and based on the analysis of medium response spectral lines dynamics, is verified experimentally. The temporal dynamics of spectral lines allows to determine relaxation time of rotational transitions as well. A question about measurement time, that is sufficient for determining of material response characteristic time, is discussed. To demonstrate the efficiency of proposed method, we treat the response of soap and chocolate under the action of terahertz pulse with a few cycles. Our investigation shows that it is possible to identify these materials with high probability.