coupling constant (spin-spin), J in analysis

https://dx.doi.org/10.1351/goldbook.C01383
A quantitative measure for nuclear spin-spin, nuclear-electron (hyperfine coupling) and electron-electron (fine coupling in EPR) coupling in magnetic resonancespectroscopy. The 'indirect' or scalar NMRcoupling constants are in a first approximation independent of the external magnetic field and are expressed in Hz.
Source:
PAC, 1994, 66, 1077 (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1101