"发射光谱测量学" can be translated into English as "Emission Spectrometry" or, more specifically in some contexts, "Emission Spectroscopic Measurement Science" (though the former is more commonly used).
"Emission Spectrometry" is a well-established term in the field of spectroscopy, referring to the measurement and analysis of the emission spectra of substances, which is a key aspect of emission spectroscopic measurement science.