If I'm a small particle in a liquid in temperature T, molecules from every direction collide in me f times per second, what is the probability that I'll collide with a particle with energy ε? What is the average energy for collisions? I think I can rephrase it to "how many times per second there will be collision with energy ε±Δε?" or "what is the energy distribution of particles in a liquid?" If it were gas, the answer would be given by the Maxwell-Boltzmann distribution, but it is a (very general) liquid. Can someone help? Thanks!