oscillator strength, fij

https://doi.org/10.1351/goldbook.O04339
Measure for integrated intensity of electronic transitions and related to the Einstein transition probability coefficient Aij by: fij=1.4992×1014 Aijs1 (λnm)2 where λ is the transition wavelength. There are, however, differing uses of f.
Source:
Green Book, 2nd ed., p. 33 [Terms] [Book]
See also:
PAC, 1996, 68, 2223. (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2257 [Terms] [Paper]