Robert Emerson (scientist)

Emerson's first "important"^[1] result was the quantification of the ratio of chlorophyll molecules to oxygen molecules produced by photosynthesis.^[1][5] Emerson and William A. Arnold found that "the yield per flash reached a maximum when just 1 out of 2500 chlorophylls absorbed a quantum".^{[5][6]: 172}

Next, in 1939, Emerson demonstrated that between 8 and 12 quanta of light were needed to produce one molecule of oxygen.^[3][7][8] These results were controversial, as they contradicted Warburg who reported 4, then 3, and finally 2 quanta.^[3] This dispute was settled after the death of both men, and it is now agreed that Emerson was correct, and the accepted modern value is 8 – 10 quanta.^[6]: 68

In 1957, Emerson reported results that are now called the Emerson effect, the excess rate of photosynthesis after chloroplasts are simultaneously exposed to light of wavelength 670 nm (red light), and 700 nm (far red light).^[2][9]

These results were later shown to be the first experimental demonstration that there are two photosynthetic reaction centres in plants.^[10]

Emerson died in the crash of American Airlines Flight 320 in New York City in 1959.