Zusammenfassung
Dielec. relaxation (DR) and optical Kerr-effect (OKE) spectra of the archetypal protic ionic liqs. Et- and propylammonium nitrate (EAN and PAN) were measured over an unusually large frequency range from 200 MHz to 10 THz at temps. (mostly) between 5 and 65°. Anal. of the low-frequency α-relaxation, assocd. with the cooperative relaxations of (DR) and (OKE) and any clusters present, indicated ...
Zusammenfassung
Dielec. relaxation (DR) and optical Kerr-effect (OKE) spectra of the archetypal protic ionic liqs. Et- and propylammonium nitrate (EAN and PAN) were measured over an unusually large frequency range from 200 MHz to 10 THz at temps. (mostly) between 5 and 65°. Anal. of the low-frequency α-relaxation, assocd. with the cooperative relaxations of (DR) and (OKE) and any clusters present, indicated that ion reorientation in EAN is decoupled from viscosity and occurs via cooperative relaxation involving large-angle jumps rather than rotational diffusion. Detailed consideration of the high-frequency parts of the DR and OKE spectra showed that the obsd. intensities were a complex combination of overlapping and possibly coupled modes. In addn. to previously identified intermol. H-bond vibrations, there are significant contributions from the librations of the cations and anions. The present assignments are consistent with the isotopic shifts obsd. for deuterated EAN.
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