Molecular rotational potentials in solid halogenated benzenes: C6Cl6, sym-C6Cl3F3, and C6F6.
スポンサーリンク
概要
- 論文の詳細を見る
In a previous paper which examined the molecular rotation in <I>sym</I>-C<SUB>6</SUB>Cl<SUB>3</SUB>F<SUB>3</SUB> crystal by the <SUP>35</SUP>Cl NQR an unrealistically long activation parameter, τ<SUB>0</SUB>, for the molecular rotation was obtained by assuming the three-fold molecular uniaxial reorientation. In order to examine the reason for such unacceptable result the relaxation time (<I>T</I><SUB>1</SUB>) data were reanalyzed with the help of the computer experiment which calculates the rotational potential function for each molecule in the crystal lattice. The computation was carried out using the 6-exponential type interatomic pair potential functions. It was found that the potential for the plane molecular rotation in the hexagonal unit cell is non-sinusoidal and has, in addition to the most stable orientation, an extra minimum where the molecules can stay for a finite time at moderately high temperatures. The rotational potential thus obtained was used successfully to reanalyze our previous <I>T</I><SUB>1</SUB> data for this material. <SUP>35</SUP>Cl NQR <I>T</I><SUB>1</SUB>'s were measured for C<SUB>6</SUB>Cl<SUB>6</SUB> crystal and analyzed using anisotropic rotational potentials. The analysis predicted possible disordered structure of this material. In the case of C<SUB>6</SUB>F<SUB>6</SUB> it was confirmed that the in-plane rotation of two crystallographically inequivalent molecules can be excited with different activation energies from each other, being consistent with the previous fluorine NMR work.
- 公益社団法人 日本化学会の論文