local efficiency of atomization, \(\varepsilon_{\text{a}}\)

in flame spectrometry
The substance fraction of atomized component in the component consumed. The efficiency of atomization is measured in a given part of the flame, usually the observation space; \(\varepsilon_{\text{a}} = \varepsilon_{\text{n}}\ \chi _{\text{s}}\ \chi _{\text{v}}\ \chi _{\text{a}}\). The signal is a function of the product \(q_{\text{v}}\ \varepsilon_{\text{a}}\), but \(\varepsilon_{\text{a}}\) is also a function of \(q_{\text{v}}\), usually decreasing at high volume rates.
Orange Book,2nd ed., p. 169
PAC, 1986, 58, 1737. 'Quantities and units in clinical chemistry: Nebulizer and flame properties in flame emission and absorption spectrometry (Recommendations 1986)' on page 1741 (https://doi.org/10.1351/pac198658121737)