The logarithm of Raman backscattering power as a function of sensing distance is numerically calculated for HF molecule with concentrations of 1016 and 1019 cm-3 at chosen wavelengths of YAG:Nd laser and the distance range 1-1000 m. The numerical solution of the lidar equation for DAS is obtained. Ranges of HF molecule concentration, sensing distances, and optimal conditions are determined.