We report on a search for electronic recoil event rate modulation signatures in the XENON100 data accumulated over a period of 4 years , from January 2010 to January 2014 .
A profile likelihood method , which incorporates the stability of the XENON100 detector and the known electronic recoil background model , is used to quantify the significance of periodicity in the time distribution of events .
There is a weak modulation signature at a period of 431 ^ { +16 } _ { -14 } days in the low energy region of ( 2.0 - 5.8 ) keV in the single scatter event sample , with a global significance of 1.9 \sigma , however no other more significant modulation is observed .
The expected annual modulation of a dark matter signal is not compatible with this result .
Single scatter events in the low energy region are thus used to exclude the DAMA/LIBRA annual modulation as being due to dark matter electron interactions via axial vector coupling at 5.7 \sigma .