Dynamics of two glass forming monohydroxy alcohols by field cycling 1H NMR relaxometry

Dynamics of Dimethylbutanols in Plastic Crystalline Phases by Field Cycling 1H NMR Relaxometry

“…For all samples in the L phase and for 3,3-DM-2 in the Cr1 phase, the NMRD curves were well reproduced (examples are shown in Figure ) considering the BPP model for R 1 IM and R 1 MR (eq with Lorentzian spectral densities) and the force-free hard-sphere model for R 1 SD (eqs and ), in agreement with a previous study on 2,2-DM-1-B and 3,3-DM-1-B . In the calculations, N H was kept fixed at all temperatures at values of 6.83 × 10 28 , 6.96 × 10 28 , and 6.70 × 10 28 spins/m 3 for 2,2-DM-1-B, 3,3-DM-1-B, and 3,3-DM-2-B, respectively.…”

“…Considering the molecular structure of the investigated alcohols (Figure ) and the phases they form in the examined temperature range, contributions arising from internal motions ( R 1 IM ) and overall molecular reorientations ( R 1 MR ) were expected in all phases. On the other hand, translational self-diffusion ( R 1 SD ) certainly contributes to relaxation in the liquid phase, as already pointed out in a previous study, but it might also affect relaxation in the ODIC phases, as reported in the literature for other plastic crystals. − ,,, …”

Nonrotational Mechanism of Polarization in Alcohols

“…Their typical size and relatively low complexity make them interesting systems to study with dielectric spectroscopy. This is why over the past decades, the interaction of electric fields with alcohols has been the object of experimental and theoretical research, − which showed many other fundamental similarities with water. , These findings notably triggered the studies of alcohols in the glassy state, an experimentally inaccessible thermodynamic region for water, , which led to the prediction of some supercooled and confined water properties, as well as deeper insights into dielectric phenomena in protonic liquids . However, the understanding on the microscopic level of the response of alcohol molecules to an alternating electric field remains far from complete. ,, …”

“…In the present work, we perform a systematic ultrabroadband dielectric spectroscopy study on a series of monohydric alcohols of increasing carbon chain lengths. In comparison with previous studies, − ,, we expand the frequency domain down to the static conductivity, and up to the terahertz range, and we consistently perform the measurements for all the alcohols with the same experimental setup. From this data, we unravel the pre-eminent role of proton intermolecular dynamics in dielectric response across the whole frequency range and show that both the static conductivity and the high-frequency dielectric polarization of alcohols can be explained by considering charge separation over intermolecular distances induced by proton tunneling.…”

Non-rotational mechanism of polarization in alcohols

“…Their typical size and relatively low complexity make them interesting systems to study with dielectric spectroscopy. That is why over the past decades, the interaction of electric fields with alcohols has been the object of experimental and theoretical research [1][2][3][4][5][6][7][8][9][10][11], which showed many other fundamental similarities with water [12,13]. These findings notably triggered the studies of alcohols in the glassy state -an experimentally inaccessible thermodynamic region for water [14,15], which led to the prediction of some supercooled [16] and confined [17] water properties, as well as deeper insights into dielectric phenomena in protonic liquids [18].…”