Home › Words › H › hartreehartreehartree · name — A surname.Definition from Wiktionary (CC BY-SA 3.0).EtymologyNamed after the British physicist Douglas Hartree (1897–1958).nameA surname.nounThe atomic unit of energy, defined as 2R_∞hc, where R_∞ is the Rydberg constant, h is the Planck constant and c is the speed of light. It equals 4.35974 attojoules.Definitions & examples from Wiktionary (CC BY-SA 3.0).Words closest in meaningBy meaning, not spelling — each word's AI semantic fingerprint, nearest first.bethe 61% match — A unit of energy equivalent to 10⁵¹ ergs, or 10⁴⁴ joules. vs hartree →atomerg 55% match — An indivisible unit of energy, according to a theory of matter put forward by Earle K. Plyler in the 1930s. vs hartree →attojoule 53% match — An SI unit of energy, work, and heat equal to 10⁻¹⁸ joules. Symbol: aJ vs hartree →petahertz 53% match — An SI unit of frequency equal to 10¹⁵ hertz. vs hartree →attohertz 52% match — An SI unit of frequency equal to 10⁻¹⁸ hertz. vs hartree →exahertz 52% match — A unit of measurement based on one quintillion hertz. vs hartree →yottahertz 51% match — A unit of measurement based on one septillion hertz. vs hartree →debye 50% match — The CGS unit of electric dipole moment, defined as 1 D = 10⁻¹⁸ statcoulomb-centimetre and computable from the SI unit coulomb-metre by multiplying by the factor 3.33564 × 10⁻³⁰. vs hartree →