Molecules still have vibrational energy at absolute zero temperature, which refers to zero-point energy. It's a fact that temperature in physics is a computation of the strength of random molecular motion. Therefore, it stands to reason that as the temperature approaches absolute zero, each motion may stop, and at the same time, molecules will also be motionless. The motion, equivalent to zero-point energy, however, never actually disappears. Fundamentals of quantum mechanics, the science of subatomic occurrences, lead to zero-point energy. The atoms that make up molecules would be distinctly placed and have precisely determined velocities, notably zero, if the molecules ever attain total repose. Molecules can never come to absolute rest since it is a fundamental tenet of quantum physics that no particle can ever hold exact values of velocity and status at the same time as per the Principle of Uncertainty.