Study of the multiplet nature in shpol'skii effect: Host n-heptane crystalline structure by X-ray diffraction and guest coronene position by ESR

TLDR: In this article, the exact position of coronene molecules in an n-heptane single crystal exhibiting Shpol'skii effect was determined using X-ray diffraction and ESR analysis.

Abstract: In order to determine the exact position of coronene molecules in an n-heptane single crystal exhibiting Shpol'skii effect, two crucial experimentas were performed: X-ray diffraction study of host n-heptane and ESR investigation of guest coronene. The X-ray experiments were carried out at 100 K; from calculations with an R value of 8% it is found that n-heptane crystallizes in a centered triclinic P 1 system. The resonance fields of the Δm = ± 1 transitions of triplet coronene were measured at 77 K as a function of the orientation of the single crystal in the cavity. Those two experiments demonstrate that the coronene molecules occupy mainly substitutional sites in the n-heptane lattice by replacing three alkane chains in the plane including the c axis.