Conversion - PPFD to Einsteins

An Einstein is defined as a mole of photons.

Therefore: µEinsteins per m² per second is identical to µmoles per m² per second. 1000 µE m^-2 s^-1 ≡ 1000 µmol m^-2 s^-1

µEinsteins were interchangeably used along with µmol m^-2 s^-1 in the 60's and 70's, but the Einstein is not a unit in the SI (International System) of units, so using moles is preferred.

For more information see:
Units, Symbols, and Terminology for Plant Physiology A Reference for Presentation of Research Results in the Plant Sciences Edited by Frank B. Salisbury Oxford University Press, 1996