Fully anharmonic IR and Raman spectra of medium-size molecular systems: accuracy and interpretation
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TLDR
This perspective sketches the recent developments in the research group toward the development of a robust and user-friendly virtual spectrometer rooted in second-order vibrational perturbation theory (VPT2) and usable also by non-specialists essentially as a black-box procedure.Abstract:
Computation of full infrared (IR) and Raman spectra (including absolute intensities and transition energies) for medium- and large-sized molecular systems beyond the harmonic approximation is one of the most interesting challenges of contemporary computational chemistry. Contrary to common beliefs, low-order perturbation theory is able to deliver results of high accuracy (actually often better than those issuing from current direct dynamics approaches) provided that anharmonic resonances are properly managed. This perspective sketches the recent developments in our research group toward the development of a robust and user-friendly virtual spectrometer rooted in second-order vibrational perturbation theory (VPT2) and usable also by non-specialists essentially as a black-box procedure. Several examples are explicitly worked out in order to illustrate the features of our computational tool together with the most important ongoing developments.read more
Citations
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Journal ArticleDOI
Vibrational Spectroscopy of Ionic Liquids
TL;DR: The conceptual basis of theoretical frameworks which have been used to interpret vibrational spectra of ionic liquids are reviewed, helping the reader to distinguish the scope of application of different methods of calculation.
Journal ArticleDOI
Aiming at an accurate prediction of vibrational and electronic spectra for medium-to-large molecules: An overview
TL;DR: In this article, the authors present a tutorial for the simulation of vibrational and vibrationally resolved electronic spectra of medium-to-large molecules, including thiophene and its smallest oligomer bithiophene.
Journal ArticleDOI
Hydrogen-bonding effects on infrared spectra from anharmonic computations: uracil-water complexes and uracil dimers
TL;DR: Experimental frequencies available for a set of four uracil-water complexes have been considered as references for the computational methodologies applied to the simulation of hydrogen-bonding effects on the infrared spectrum, obtaining average uncertainties and improved description within 10 cm(-1) by hybrid B2PLYP/B3LYP-D3 approaches.
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Competition between H2O and (H2O)2 reactions with CH2OO/CH3CHOO
Liang-Chun Lin,Liang-Chun Lin,Hung-Tzu Chang,Chien-Hsun Chang,Wen Chao,Wen Chao,Mica C. Smith,Mica C. Smith,Chun-Hung Chang,Jim J. Lin,Jim J. Lin,Kaito Takahashi +11 more
TL;DR: It is found that the theoretical rate coefficients reproduce the experimental results of CH2OO for a wide range of temperatures, and for Criegee intermediates with a hydrogen atom on the same side as the terminal oxygen atom, the reaction with water vapor will likely dominate the removal processes of these CIs in the atmosphere.
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Snapshots of Proton Accommodation at a Microscopic Water Surface: Understanding the Vibrational Spectral Signatures of the Charge Defect in Cryogenically Cooled H(+)(H2O)(n=2-28) Clusters.
Joseph A. Fournier,Conrad T. Wolke,Mark A. Johnson,Tuguldur T. Odbadrakh,Kenneth D. Jordan,Shawn M. Kathmann,Sotiris S. Xantheas +6 more
TL;DR: Considerations indicate that, in addition to the sizable anharmonic couplings, the position of the OH stretch most associated with the excess proton can be traced to large increases in the electric fields exerted on the embedded hydronium ion upon formation of the first and second solvation shells.
References
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