Positronium formation studies in solid molecular complexes: Triphenylphosphine oxide–triphenylmethanol

Abstract

Abstract Positronium formation in triphenylphosphine oxide (TPPO), triphenylmethanol (TPM), and systems [TPPO (1− X ) ⋅TPM X ] has been studied. The low probability of positronium formation in complex [TPPO 0.5 ⋅TPM 0.5 ] was attributed to strong hydrogen bond and sixfold phenyl embrace interactions. These strong interactions in complex reduce the possibility of the n - and π -electrons to interact with positrons on the spur and consequently, the probability of positronium formation is lower. The τ 3 parameter and free volume (correlated to τ 3 ) were also sensitive to the formation of hydrogen bonds and sixfold phenyl embrace interactions within the complex. For physical mixture the positron annihilation parameters remained unchanged throughout the composition range.