"To absorb those molecules" means to take in or soak up the molecules into something, typically referring to a substance or material that can take in or combine with other molecules. Full definition
In susceptible dogs, they are unable to absorb these molecules across the small intestines because they lack certain carrier molecules. (mypetneedsthat.com)
They analyzed the samples for colored dissolved organic matter, which contains light - absorbing molecules from the breakdown of plant polymers such as lignin. (sciencemag.org)
«Dark joy» perfectly characterizes the action of gossip, the resulting sin, the objectification of another person, the turning of a human being into a thing, the tool by which we build an illusion of inclusion within a rather porous clique» porous because we are like sponges, absorbing molecules of spite at the coffee machine and releasing them, sometimes with malice, in the elevator. (firstthings.com)