[en] The laser isotope separation by the method of infrared multiphoton decomposition (IRMPD) is at present the most promising of the laser-based techniques for the enrichment of deuterium on a large scale. However, it cannot be used directly with two largest sources of deuterium, water and methane. It is necessary to incorporate deuterium into working molecules, and this study concerns the IRMPD of neat and isotopic mixtures of 1,1,1-trichloroethane (TCE), one kind of such working molecules. The TCE has very simple photochemistry. The experiment on three different types was performed. High isotopic selectivity is possible with 1,1,1-TCE. High decomposition yield with the neat samples did not necessarily translate into high yield with the dilute samples. (K.I.)