Exploring the Reliability of DFT Calculations of the Infrared and Terahertz Spectra of Sodium Peroxodisulfate

Kendrick, John; Burnett, Andrew

doi:10.1007/s10762-019-00643-8

Cited by 18 publications

(24 citation statements)

References 60 publications

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“…In the case of INS, the Perdew-Burke-Ernzerhof (PBE)-calculation has been repeatably reported to underestimate of the C=O stretching mode [173]. For IR spectra, the most discrepancies between calculation and experiment are always found in the far infrared region (low wave numbers) [174,175]. However, it is definitely less common when periodic DFT and not a calculation on a single molecule is performed.…”

Section: Vibrational Propertiesmentioning

confidence: 99%

Periodic DFT Calculations—Review of Applications in the Pharmaceutical Sciences

2020

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In the introduction to this review the complex chemistry of solid-state pharmaceutical compounds is summarized. It is also explained why the density functional theory (DFT) periodic calculations became recently so popular in studying the solid APIs (active pharmaceutical ingredients). Further, the most popular programs enabling DFT periodic calculations are presented and compared. Subsequently, on the large number of examples, the applications of such calculations in pharmaceutical sciences are discussed. The mentioned topics include, among others, validation of the experimentally obtained crystal structures and crystal structure prediction, insight into crystallization and solvation processes, development of new polymorph synthesis ways, and formulation techniques as well as application of the periodic DFT calculations in the drug analysis.

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Section: Vibrational Propertiesmentioning

confidence: 99%

Periodic DFT Calculations—Review of Applications in the Pharmaceutical Sciences

2020

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“…In order to explore the variability between the simulation methods, the calculated results can be internally compared against each other by examining the cross-correlation between the theoretical results, as shown Figure 3. The cross-correlation analysis was modified based on a previously reported method [11]. For each normal mode, the predicted transition frequencies were normalized,…”

Section: Naphthalenementioning

confidence: 99%

“…FTIR and Raman), terahertz vibrations are much more complex and depend on many factors, making assignment difficult. [1,2,4,[11][12][13][14][15] Computational methods have been successfully used to assign the predict vibrational spectra with success. However, the simulation of low-frequency vibrations presents a greater challenge compared to mid-infrared motions, due to the incredibly weak forces that dictate terahertz motions.…”

Section: Introductionmentioning

confidence: 99%

Assessing the Performance of Density Functional Theory Methods on the Prediction of Low-Frequency Vibrational Spectra

Banks

Song

Ruggiero

2020

J Infrared Milli Terahz Waves

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The low-frequency (terahertz) dynamics of condensed phase materials provide valuable insight into numerous bulk phenomena. However, the assignment and interpretation of experimental results requires computational methods due to the complex mode-types that depend on weak intermolecular forces. Solid-state density functional theory has been used in this regard with great success, yet the selection of specific computational parameters, namely the chosen basis set and density functional, has a profound influence on the accuracy of predicted spectra. In this work, the role of these two parameters is investigated in a series of organic molecular crystals, in order to assess the ability of various methods to reproduce intermolecular forces, and subsequently experimental terahertz spectra. Specifically, naphthalene, oxalic acid, and thymine were chosen based on the varied intermolecular interactions present in each material. The results highlight that unconstrained geometry optimizations can be used as an initial proxy for the accuracy of interatomic forces, with errors in the calculated geometries indicative of subsequent errors in the calculated low-frequency vibrational spectra, providing a powerful metric for the validation of theoretical results. Finally, the origins of the observed shortcomings are analyzed, providing a basic framework for further studies on related materials. File list (2) download file view on ChemRxiv main.pdf (7.38 MiB) download file view on ChemRxiv ESI.pdf (5.55 MiB) Noname manuscript No.

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“…The intensities of THz bands constitute another valid source of information about the crystal symmetry, intermolecular interactions, and the nature of the vibrational modes. The potentials of intensity data have been well-recognized in the past by many groups. − …”

Section: Introductionmentioning

confidence: 99%

A Quantitative Interpretation for the Difference of Terahertz Spectra of dl- and l-Alanine: Origins of Infrared Intensities in Terahertz Spectroscopy

et al. 2021

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The absorption spectra of l-, d-, and dl-alanine in the low-frequency region were measured by terahertz (THz) time-domain spectroscopy (053903Appl. Phys. Lett.200586). It has been observed that several absorption bands have a significant difference between the enantiomers (l- and d-alanine) and the racemic compound (dl-alanine) in their peak frequencies. In this work, we calculate the THz spectra of dl- and l-alanine by solid-state density functional theory to quantitatively interpret the spectral difference. The two systems give rise to similar distributions of normal modes in the 5–80 cm–1 frequency range; however, the THz spectra of both crystals are different. During our work, we found two critical aspects regarding the intensities of the THz bands. One aspect, as is known for a molecular crystal, is that the cancellation of the transition dipole moments in the unit cell: Even if an individual molecule in a unit cell has a nonzero transition dipole moment, the total transition dipole moment of the unit cell is zero due to the cancellation of the contributions from the molecules. The second aspect is that these THz normal modes of dl- and l-alanine are dominated by the intermolecular translations, which are intrinsically infrared (IR)-inactive if the molecules are not polarized. Our analysis shows that the IR intensities of these “almost-pure” intermolecular translations are due to a subtle balance between the IR activities induced by the polarization effect of translations and the IR activities of the librations and intramolecular vibrations, which have marginal presences in these normal modes.

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Exploring the Reliability of DFT Calculations of the Infrared and Terahertz Spectra of Sodium Peroxodisulfate

Cited by 18 publications

References 60 publications

Periodic DFT Calculations—Review of Applications in the Pharmaceutical Sciences

Periodic DFT Calculations—Review of Applications in the Pharmaceutical Sciences

Assessing the Performance of Density Functional Theory Methods on the Prediction of Low-Frequency Vibrational Spectra

A Quantitative Interpretation for the Difference of Terahertz Spectra of dl- and l-Alanine: Origins of Infrared Intensities in Terahertz Spectroscopy

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