Reply to ``Comment on `Light scattering study of the phase transition in sym-triazine' ''
Rae’s1 comments on the author’s paper concerning the phase transition in sym‐triazine2 are answered. (AIP)
On the phase transition in benzil
The phase transition in crystalline benzil [(C6H5CO)2] at 84 K is investigated through Brillouin scattering. The major experimental findings are two transverse acoustic phonon modes exhibiting softening near the phase transition, a longitudinal acoustic mode that is temperature sensitive, and the ratio of the Rayleigh peak intensity to the soft mode intensity behaves anomalously. These results are discussed using a theory developed for an elastic phase transition in sym‐triazine (C3N3H3). It is found that bilinear‐coupling terms involving strains and the order parameter can explain transverse mode behavior but not that of the longitudinal acoustic mode.
HIGH RESOLUTION RAMAN SPECTROSCOPY OF GASES: VII. ROTATIONAL SPECTRA OF s-TRIAZINE AND s-TRIAZINE-d3
The pure rotational Raman spectra of s-triazine (C3H3N3) and s-triazine-d3 (C3D3N3) vapor were photographed in the second order of a 21-ft. grating spectrograph. The rotational constants were found to be B0(C3D3N3) = 0.21460 ± 0.00008 cm−1 and B0(C3D3N3) = 0.19358 ± 0.00015 cm−1. These values, together with the assumption that the molecule is planar and has a CH bond length of 1.084 A, give the following values for the structural parameters: r0(CN) = 1.338 ± 0.001 A, NCN = 127°, and CNC = 113°.