Study of polymorphism and torsional motions in 3-chloro-4-methylaniline using 35Cl NQR (nuclear quadrupole resonance)

Abstract

35Cl nuclear quadrupole resonance (NQR) in three polymorphic phases of 3-chloro-4-methylaniline is detected for the first time. Out of these, two phases (α and γ) are stable and the other (β) is found to be metastable. The β phase is found to transform to the stable γ phase with respect to time. The formation of the β and γ phases are discussed in terms of defects and strains. The temperature dependence of NQR lines in the range 77–292 K in all three phases is studied in detail. On the basis of a modified Bayer's theory the torsional frequencies and their temperature coefficients are computed.