Infrared spectroscopic study of the phase transitions in CsNO3, RbNO3 and NH4NO3

Phase transitions of CsNO3 (II-I), RbNO3 (IV-III-II) and NH4NO3 (V-IV-III-II-I) have been studied by i.r. spectroscopy. The study has provided useful information on the changes in the dispositions of the ions during the phase transitions.

Infrared and Nuclear Quadrupole Resonance Studies of the Phase Transitions of Para-dichlorobenzene

The α→γ→α→β transitions of para-dichlorobenzene have been studied by employing infrared and n.q.r. spectroscopy as well as differential scanning calorimetry. The γ phase is associated with considerably higher values of some of the intramolecular vibration frequencies. The α→γ transition shows athermal nucleation behaviour as in martensitic transitions. Intermolecular vibration bands around 46 and 85 cm–1 present in γ and α phases disappear in the β phase. The α→β transition seems to be associated with some orientational disorder.

Ruthenium-Oxygen Coordination-Driven Self-Assembly of a Ru-8(II) Incomplete Prism: Synthesis, Structure, and Shape-Selective Molecular Recognition Study

Coordination-driven self-assembly of 1,3,5-benzenetricarboxylate (tma; 1) and oxalato-bridged p-cymeneruthenium(II) building block Ru-2(mu-eta(4)-C2O4)(MeOH)(2)(eta(6)-p-cymene)(2)](O3SCF3)(2) (2) affords an unusual octanuclear incomplete prism Ru-8(eta(6)-p-cymene)(8)(tma)(2)(mu-eta(4)-C2O4)(2)(OMe)(4)](O3SCF3)( 2) (3), which exhibits a remarkable shape-selective binding affinity for neutral phenolic compounds via hydrogen-bonding interactions (p-cymene = p-(PrC6H4Me)-Pr-i). Such a binding was confirmed by single-crystal X-ray diffraction analysis using 1,3,5-trihydroxybenzene as an analyte.

Frequency-comb-referenced molecular spectroscopy in the mid-infrared region

A simple method for absolute frequency measurements of molecular transitions in the mid-infrared region is reported. The method is based on a cw singly-resonant optical parametric oscillator (SRO), which is tunable from 3.2 to 3.45 µm. The mid- infrared frequency of the SRO is referenced to an optical frequency comb through its pump and signal beams. Sub-Doppler spectroscopy and absolute frequency measurement of the P(7) transition of the ν3 band of CH4 are demonstrated.