  The scintillation yield for recoil Ar ions of 5 to 250 keV energy in liquid
argon have been evaluated for direct dark matter searches. Lindhard theory is
taken for estimating nuclear quenching. A theoretical model based on a
biexcitonic diffusion-reaction mechanism is performed for electronic
(scintillation) quenching. The electronic LET (linear energy transfer) is
evaluated and used to obtain the initial track structure due to recoil Ar ions.
The results are compared with experimental values reported for nuclear recoils
from neutrons. The behavior of scintillation and ionization on the field are
discussed. with notes on radiation physics and chemistry for dark matter
searches.

Instrumentation and Detectors