Related Experiment Video
Updated: Aug 15, 2026

Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method
Published on: July 19, 2019
Anomalous temperature dependence of nuclear quadrupole interactions in strongly hydrogen-bonded systems from first
1Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany. schmidt@mpip-mainz.mpg.de
Abstract:
We present an analysis of the effect of finite temperatures on the deuteron nuclear quadrupole coupling constants in a strongly hydrogen-bonded molecular crystal by means of first-principles Car-Parrinello molecular-dynamics simulations. Our findings agree well with experiments and provide a microscopic explanation of the anomalous increase of the quadrupole coupling in this class of systems. We show that a simple model based on the anharmonicity of the hydrogen bond potential fails to describe the temperature dependence of the couplings even qualitatively. Instead, the inclusion of fluctuations and disorder in terms of atomic motion of the surrounding molecules turns out to be important to obtain the correct magnitude of the temperature effect.
Related Concept Videos
Atomic Nuclei: Nuclear Spin State Population Distribution
Hydrogen Bonds
Hydrogen Bonds
Atomic Spectroscopy: Effects of Temperature
At thermal equilibrium, the relative populations of excited and ground state atoms can be estimated using the Maxwell–Boltzmann distribution. For example, an increase in temperature from...
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
¹H NMR: Interpreting Distorted and Overlapping Signals
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...

