TY - JOUR

T1 - Proton delocalization and tunneling in terephthalic acid

T2 - Raman spectroscopic study

AU - Kolesov, Boris A.

PY - 2020/3

Y1 - 2020/3

N2 - Raman spectra of terephthalic acid (TPA), regular TPA(H) and deuterated TPA(D), were recorded in the temperature range of 5–300 K. It is shown that temperature dependences of vibration frequencies provide both the data on proton tunneling in tautomeric bonds and the data on phonon-assisted proton jumps. At the same time, the quantum delocalization of proton (deuteron), i.e. penetration of proton (deuteron) density distribution function into the neighboring potential well, affects the temperature dependence of the frequency of translational vibrations O⋅⋅⋅O and is observed at T ≤ 180 K in TPA(H) and at T ≤ 170 K in TPA(D). Proton tunneling through the barrier affects the temperature dependence of the frequency of C[dbnd]O stretchings in carboxyl groups and is observed at T ≤ 100 K. No coordinated proton (deuteron) jumps over the potential barrier with a rate capable to change notably the vibration frequency of C[dbnd]O bonds was observed in TPA over the entire temperature range.

AB - Raman spectra of terephthalic acid (TPA), regular TPA(H) and deuterated TPA(D), were recorded in the temperature range of 5–300 K. It is shown that temperature dependences of vibration frequencies provide both the data on proton tunneling in tautomeric bonds and the data on phonon-assisted proton jumps. At the same time, the quantum delocalization of proton (deuteron), i.e. penetration of proton (deuteron) density distribution function into the neighboring potential well, affects the temperature dependence of the frequency of translational vibrations O⋅⋅⋅O and is observed at T ≤ 180 K in TPA(H) and at T ≤ 170 K in TPA(D). Proton tunneling through the barrier affects the temperature dependence of the frequency of C[dbnd]O stretchings in carboxyl groups and is observed at T ≤ 100 K. No coordinated proton (deuteron) jumps over the potential barrier with a rate capable to change notably the vibration frequency of C[dbnd]O bonds was observed in TPA over the entire temperature range.

KW - Deuteration

KW - Hydrogen bonds

KW - molecular crystals

KW - Tautomerism

KW - Terephthalic acid

KW - SOLID-STATE NMR

KW - NUCLEAR-MAGNETIC-RESONANCE

KW - NEUTRON-SCATTERING

KW - DYNAMICS

KW - CRYSTALS

KW - HYDROGEN-BONDS

UR - http://www.scopus.com/inward/record.url?scp=85075919751&partnerID=8YFLogxK

U2 - 10.1016/j.jpcs.2019.109288

DO - 10.1016/j.jpcs.2019.109288

M3 - Article

AN - SCOPUS:85075919751

VL - 138

JO - Journal of Physics and Chemistry of Solids

JF - Journal of Physics and Chemistry of Solids

SN - 0022-3697

M1 - 109288

ER -