Answer:
Atomic emission is more sensitive to flame instability than atomic absorption because atomic emission is based on the analysis of light emitted from excited atoms in the flame. In contrast, atomic absorption is based on light absorption by the flame's particles.
Flame instability can lead to changes in the temperature and pressure of the flame, which can affect the excited states of the atoms in the flame. When the flame is unstable, it can cause fluctuations in the number of excited atoms and the length of time they stay excited. This, in turn, can lead to fluctuations in the amount of light emitted by the excited atoms, making it more difficult to accurately measure the analyte concentrations in the sample using atomic emission spectroscopy.
On the other hand, atomic absorption spectroscopy is less sensitive to flame instability because the light absorption by the atoms in the flame is not as dependent on the excitation states of the atoms. The atoms in the flame absorb light at specific wavelengths regardless of their excited states. Hence, fluctuations in the excited state populations have less of an impact on the absorption signal. However, atomic absorption spectroscopy can still be affected by other factors, such as changes in the temperature and pressure of the flame and the presence of other interfering species in the sample.