title: Field induced changes in the ring/chain equilibrium of hydrogen bonded structures: 5-methyl-3-heptanol.
abstract: Using non-linear dielectric techniques, we have measured the dynamics of 5-methyl-3-heptanol at a temperature at which the Kirkwood correlation factor gK indicates the coexistence of ring- and chain-like hydrogen-bonded structures. Steady state permittivity spectra recorded in the presence of a high dc bias electric field (17 MV/m) reveal that both the amplitude and the time constant are increased by about 10% relative to the low field limit. This change is attributed to the field driven conversion from ring-like to the more polar chain-like structures, and a direct observation of its time dependence shows that the ring/chain structural transition occurs on a time scale that closely matches that of the dielectric Debye peak. This lends strong support to the picture that places fluctuations of the end-to-end vector of hydrogen bonded structures at the origin of the Debye process, equivalent to fluctuations of the net dipole moment or gK. Recognizing that changes in the ring/chain equilibrium constant also impact the spectral separation between Debye and α-process may explain the difference in their temperature dependence whenever gK is sensitive to temperature, i.e., when the structural motifs of hydrogen bonding change considerably.
authors.affiliation: School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, USA.
authors.forename: Amanda R
authors.initials: AR
authors.lastname: Young-Gonzales
authors.affiliation: School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, USA.
authors.forename: Ranko
authors.initials: R
authors.lastname: Richert