In this work, absorption/desorption isotherms of the LaNi3.6Mn0.3Al0.4Co0.7 alloy, have been determined from the experimental data at three temperatures (T-Fluid = 298 K, T-Fluid = 303 K, and TFluid- = 313 K). However, the experimental isotherms are compared with a proposed theoretical model. The physicochemical parameters of the proposed model are determined from the experimental data. Using these parameters, the absorption and desorption processes of hydrogen by the LaNi(3.6)Mn(0.3)Al(0.4)Co(0.7 )alloy can be compared. During the absorption/desorption process, the behaviors of each parameter are studied under the effect of temperature and pressure. In addition, internal energy, entropy, and enthalpy are calculated by using the proposed model. On the other hand, the temperature and pressure effects on the variation of these functions have been studied. The calculated physicochemical parameters suggested that the hydrogen absorption/desorption process in the LaNi3.6Mn0.3Al0.4Co0.7 alloy was feasible, spontaneous and exothermic in nature. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.