
1) Unit of energy
Found on
https://www.crosswordclues.com/clue/hartree

(E
h) Compare with atomic unit. The atomic unit of energy, equal to 4.359 743 81 × 10
-18 J ± 0.000 000 34 × 10
-18 J [1998 CODATA values].
Found on
http://antoine.frostburg.edu/chem/senese/101/glossary/h.shtml

The hartree energy is approximately the electric potential energy of the hydrogen atom in its ground state and, by the virial theorem, approximately twice its ionization energy; the relationships are not exact because of the finite mass of the nucleus of the hydrogen atom and relativistic corrections. The hartree is usually used as a unit of energ...
Found on
http://en.wikipedia.org/wiki/Hartree
No exact match found.