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abstraction > mathematical concept > number > constant > fundamental physical constant > atomic constant

atomic constant
subject			fact

atomic constant	is a kind of fundamental physical constant
fundamental physical constant	has value changes in value are due solely to an increase in measurement accuracy or convention
	has accuracy
	has unit

Kinds of atomic constant :

• Bohr radius (12 facts) (a₀, a₀) - A unit of length based on the radius of the first Bohr orbit of hydrogen 1.
• classical electron radius (6 facts) (r_e)
• Fermi coupling constant (5 facts) (G_f/(hc)³)
• fine-structure constant (9 facts) (α, α) - A "coupling constant," e² / h bar c, approximately 1/137, that measures the strength of an interaction between a charged particle and the electromagnetic field. It gives a rough measure of the relative importance of relativistic and spin effects in the spectra of atoms., A parameter that measures the strength of the electromagnetic force. The fine-structure constant is a combination of other fundamental constants of nature - the electrical charge of the electron, the speed of light, and Planck's constant of quantum mechanics., A coupling constant e² / h bar c, approximately equal to 1/137 (where e is the electron charge, h bar is Plancks constant, and c is the speed of light), that measures the strength of the interaction between a charged particle and the electromagnetic field.
• Hartree energy (6 facts) (E_h)
• quantum of circulation (5 facts) (h/2m_e)
• Rydberg constant (6 facts) (R_∞)
• Thomson cross section (6 facts) (σ_e)
• weak mixing angle (5 facts) (sin²θ_W)