collision frequency, \(z_{\text{A}}(\text{A})\)

https://doi.org/10.1351/goldbook.C01166

Average number of collisions experienced by a molecule A with other molecules A (or B) in a time interval divided by that time interval.

Source:
Green Book, 2^nd ed., p. 56 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)

See also:
PAC, 1996, 68, 149. 'A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)' on page 159 (https://doi.org/10.1351/pac199668010149)