## coulomb integral, $$H_{\text{rr}}$$

https://doi.org/10.1351/goldbook.C01366
Integral over space of the type ∫ ψ r ∗ H ̂ ψ r ⁢ d τ where H(hat) is the hamiltonian operator containing electrostatic potential energy terms and ψ is a one-electron wavefunction.
Source:
Green Book, 2nd ed., p. 17 (https://dev.goldbook.iupac.org/files/pdf/green_book_2ed.pdf)