This work describes calculational methods and the results of systematic calculations of the thermodynamic properties, composition, spectral and mean absorption coefficients for air, water, silicon dioxide and the atmosphere of Mars (0.965 CO2+ 0.035 N-2). The range of the considered temperatures from 0.1 to 10(3) eV includes the molecular state of the substances, dissociative gas, low temperature plasma and multicharge plasma. The selected density range rho = 10(-9)-10(-2) g cm(-3) includes the most interesting states for applications. The main mechanisms which determine the absorption coefficients of gases and plasma (inverse bremsstrahlung; photoionization from the ground and excited states of particles; photodissociation of molecules; photoionization from internal particle shells; electronic-vibrational transitions in molecules I line absorption by atoms and ions) were taken into account. Absorption coefficients were determined for photon energies epsilon = 3 x 10(-2)-10(4) eV.