Positron Annihilation Lifetime Analysis of Left- and Right-Handed Alanine Single Crystals
B. Eren a, F. Wu b, E. Eren a, Y.C. Jean b and J.D. Van Hornb
aDepartment of Chemistry, Faculty of Science and Arts, Bilecik Şeyh Edebali University, 11210 Bilecik, Turkey
bDepartment of Chemistry, University of Missouri-Kansas City, 5110 Rockhill Rd., Kansas City, Missouri 64110, USA
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Studies of the interaction of polarized light or particles (including electrons, e-, or positrons, e+) with asymmetric forms of matter has been of interest to scientists since the discovery of chirality and the subsequent development of particle physics. Researchers have been interested in e+ interactions with chiral molecules for decades, but with mixed and indecisive results. After reviewing the field, we speculated that the e+ or positronium (Ps) might interact differently with chiral pairs of large single crystals, i.e., the left-handed or right-handed asymmetric forms of the crystals - and subsequently observed significant differences in "free positron" annihilation and intensities in the evaluation of left-handed or right-handed quartz single crystals. This result may be understood to be a "particle stereo-recognition" phenomenon. To extend this line of inquiry we crystallized mm scale L- or D-alanine crystals and performed positron annihilation lifetime spectroscopy measurements using a 22Na positron source. Alanine crystals were obtained via slow evaporation of water in a Dewar, or from water/acetone solvent in a temperature-controlled environment. These methods resulted in small ( ≈0.5 cm/side) or large ( ≥1.0 cm/side) crystals, respectively. While some intensity (I2) results from left-handed and right-handed crystals varied in positron annihilation lifetime spectroscopy analysis, the errors associated with the measurements do not indicate a stereo-recognition of alanine via positron interactions.

DOI: 10.12693/APhysPolA.132.1456
PACS numbers: 78.70.Bj, 82.30.Gg, 34.80.-i, 87.15.B-