Angular momentum is a measure of rotational motion, action is a physical quantity related to energy, and spin is an intrinsic property of particles.

1 hplanck = 6.62607015e-34 m^2*kg/s (#3 of 7 SI Defining constants); The hplanck is a physical unit representing the Planck constant, denoted as h, used in quantum mechanics to quantify angular momentum and action. It is one of the seven SI defining constants.

1 hbar = 1.0545718176461565e-34 m^2*kg/s (also called Dirac constant); "hbar" is a physical unit representing the reduced Planck constant. It is used in quantum mechanics to quantify angular momentum, action, and spin.