  The energy losses of ~(0.273-3.334) MeV protons in Lithium Fluoride thin
films deposited by vacuum evaporation onto self-supporting Al foils have been
measured using the transmission method. The thicknesses of selected and used
Lithium Fluoride/Al target samples were accurately determined via systematic
energy loss measurements for alpha particles from a very thin mixed
241Am/239Pu/233U radioactive source. The samples were investigated in detail
for their stoichiometry and their impurity contents by backscattering
Rutherford spectrometry and nuclear reaction analysis. Then, Lithium Fluoride
stopping powers have been determined with overall relative uncertainty of less
than 2.7% arising mainly from errors in the determination of target sample
thicknesses. These S(E) data are reported and discussed in comparison to
previous experimental data sets from the literature and to values calculated by
the Sigmund-Schinner binary collision stopping theory both for molecular
Lithium Fluoride and for the Lithium Fluoride compound assuming the Bragg's
additivity rule. Our S(E) data show to be in excellent agreement with the
latter theory for molecular Lithium Fluoride over the whole proton energy range
explored, which supports the use of modified hydrogenic wave functions for
evaluating atomic shell corrections in the case of low-Z2 target materials. In
contrast, they exhibit a slightly increasing deviation from theoretical values
derived for the Lithium Fluoride compound with assuming stopping force
additivity as the proton energy decreases from ~400 Kev towards lower proton
velocities.
