Intermolecular anharmonicity in molecular crystals: interplay between experimental low-frequency dynamics and quantum quasi-harmonic simulations of solid purine.
Michael T RuggieroJ Axel ZeitlerAlessandro ErbaPublished in: Chemical communications (Cambridge, England) (2018)
The intermolecular anharmonic potential of crystalline purine is probed by means of temperature-dependent terahertz time-domain spectroscopy, low-frequency Raman scattering, X-ray diffraction, and ab initio quasi-harmonic quantum-chemical simulations. As temperature increases, anharmonicity in the intermolecular interactions results in strongly anisotropic thermal expansion - with a negative thermal expansion along the b crystallographic axis - yielding corresponding bulk structural modifications. The observed thermally-induced shifts of most vibrational bands in the terahertz region of the spectra are shown to arise from volume-dependent thermal changes of the hydrogen-bond pattern along the a and b crystallographic axes.
Keyphrases
- energy transfer
- molecular dynamics
- monte carlo
- density functional theory
- high resolution
- quantum dots
- solid state
- molecular dynamics simulations
- room temperature
- single molecule
- high glucose
- oxidative stress
- diabetic rats
- risk assessment
- human health
- mass spectrometry
- dual energy
- computed tomography
- crystal structure
- climate change
- endothelial cells