Angle-resolved photoemission (ARPES) spectrum of a Cu(111) surface state using 21.22 eV photons at T=300K. Intensity is color coded as electron counts per kinetic energy and emission angle channel. Fermi level is imaged at 16.64 eV.
<a href="//commons.wikimedia.org/wiki/User:Ponor" title="User:Ponor">Ponor</a>
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<span class="int-own-work" lang="en">Own work</span>