"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 and concise).
Emission Spectrometry is the standard and widely accepted term in the scientific community for the study and measurement of emission spectra.
If you want to emphasize the measurement aspect more explicitly, you could use "Emission Spectroscopic Measurement Science", but this is less common and may come across as overly verbose in most contexts.
In general, "Emission Spectrometry" is the preferred and most accurate translation.