Nuclear spin-lattice relaxation in solid and liquid 15N2 and 14N2

Molecular rotation and volume dependence of the thermal conductivity in liquid N2

“…The calculations carried out for the components of the heat capacity C v reveal a jump of C rot towards its increasing at the point of crystal-liquid phase transition. This is in good agreement with data of references [10,11,24,25], indicating that the orientational ordering of molecules in liquid N 2 in the range above the melting temperature is higher than in the β-phase of crystalline N 2 at premelting temperatures.…”

“…As temperature rises, the orientational disordering (OD) processes in N 2 start to intensify in the high-temperature solid β-phase and increases further intensively in liquid phase immediately above melting temperature (63.15K [11]). The direct evidences for these OD processes came from the exper-3602-1 iments cited in [8][9][10][11][12][13]. In the solid β-phase of N 2 the frequency of reorientations varies with the temperature from 9.5 × 10 11 s −1 to 5.5 × 10 12 s −1 immediately before melting [8].…”

“…In the solid β-phase of N 2 the frequency of reorientations varies with the temperature from 9.5 × 10 11 s −1 to 5.5 × 10 12 s −1 immediately before melting [8]. According to [9,10], a negative jump of the spin-lattice relaxation time in N 2 is observed at the melting temperature testifying that the rotation of nitrogen molecules in the liquid phase is more hindered than that in the solid one. This is due to the formation of a structure, where molecules can make free precession in the βphase of solid N 2 ; such a structure is not implemented in the liquid phase because of an irregular particle arrangement and thermal fluctuation effects [11].…”

Lewis Acid Enhancement of Proton Induced CO2 Cleavage: Bond Weakening and Ligand Residence Time Effects

“…The triplet for the 13 CO 2 unit of isotopically labeled 4-13 C moves downfield relative to 2 (218.9 ppm, C 6 D 6 ) and exhibits smaller 2 J(C,P) scalar coupling (11.47 Hz). Akin to 3, the 11 B and 19 F NMR data are consistent with four-coordinate boron.…”

“…18 These short and near equivalent T 1 times suggest an exchange process that enables new relaxation pathways unavailable to the free small molecules. 19 In the case of CO 2 , exchange was confirmed by magnetization transfer. The high lability of the CO 2 ligand was reflected in the reactivity of 2.…”