Calculation of Vibrational Frequencies by Molecular Mechanics

Hotokka, Matti

doi:10.1002/0470027320.s4204

Cited by 2 publications

(3 citation statements)

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“…Band position: Molecular mechanics tells us that the band position (in units of cm −1 or in vibration frequency) of a given vibrational mode is proportional to the restoring force of any stretching or bending M-O bond motion, or more specifically to the square root of the spring constant of the corresponding bond configuration (Hotokka, 2006). Therefore, band position gauges the propensity of the vibrating atoms (i.e., the oxygens in LiMO 2 ) to remain in their equilibrium position.…”

Section: Discussionmentioning

confidence: 99%

“…Although factor group analysis provides the expected number of Raman active vibrations and an approximate picture of the corresponding atomic displacements (Fateley et al, 1971), the prediction of band frequencies requires an explicit modeling of classical or quantum mechanical atomic interactions (i.e. bonding) (Hotokka, 2006;Matsuura and Yoshida, 2006). Electronic structure calculations are equally important to describe the band intensities, which depend on the effect that the atomic displacements have on the dielectric properties of the lattice (Keresztury, 2006;Maschio et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

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In situ and Operando Raman Spectroscopy of Layered Transition Metal Oxides for Li-ion Battery Cathodes

2018

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In situ and operando Raman spectroscopy is proposed to provide unique means for deeper fundamental understanding and further development of layered transition metal LiMO 2 (M = Ni, Co, Mn) oxides suitable for Li-ion battery applications. We compare several spectro-electrochemical cell designs and suggest key experimental parameters for obtaining optimum electrochemical performance and spectral quality. Studies of the most practically relevant LiMO 2 compositions are exemplified with particular focus on two experimental approaches: (1) lateral and axial Raman mapping of the electrode's (near-) surface to monitor inhomogeneous electrode reactions and (2) time-dependent singleparticle spectra during cycling to analyze the Li x MO 2 lattice dynamics as a function of lithium content. Raman Spectroscopy is claimed to provide a unique real-time probe of the M-O bonds, which are at the heart of the electrochemistry of LiMO 2 oxides and govern their stability. We highlight the need for further fundamental understanding of the relationships between the spectroscopic response and oxide lattice structure with particular emphasis on the development of a theoretical framework linking the position and intensity of the Raman bands to the local Li x MO 2 lattice configuration. The use of complementary experimental techniques and model systems for validation also deserve further attention. Several novel LiMO 2 compositions are currently being explored, especially containing dopings and coatings, and Raman spectroscopy could offer a highly dynamic and convenient tool to guide the formulation of high specific charge and long cycle life LiMO 2 oxides for next-generation Li-ion battery cathodes.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

In situ and Operando Raman Spectroscopy of Layered Transition Metal Oxides for Li-ion Battery Cathodes

2018

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“…MM can simply be viewed as a ball-and-spring model of atoms and molecules with classical forces between them. 40 Such forces are accounted by potential energy functions with respect to such structural features as bond length, bond angles, and torsional angles. Potential energy functions are equipped with parameters designed to reproduce experimental properties.…”

Section: Computer-aided Drug-design (Cadd) Approachesmentioning

confidence: 99%

Quantum mechanics implementation in drug-design workflows: does it really help?

Arodola¹,

Soliman²

2017

DDDT

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The pharmaceutical industry is progressively operating in an era where development costs are constantly under pressure, higher percentages of drugs are demanded, and the drug-discovery process is a trial-and-error run. The profit that flows in with the discovery of new drugs has always been the motivation for the industry to keep up the pace and keep abreast with the endless demand for medicines. The process of finding a molecule that binds to the target protein using in silico tools has made computational chemistry a valuable tool in drug discovery in both academic research and pharmaceutical industry. However, the complexity of many protein–ligand interactions challenges the accuracy and efficiency of the commonly used empirical methods. The usefulness of quantum mechanics (QM) in drug–protein interaction cannot be overemphasized; however, this approach has little significance in some empirical methods. In this review, we discuss recent developments in, and application of, QM to medically relevant biomolecules. We critically discuss the different types of QM-based methods and their proposed application to incorporating them into drug-design and -discovery workflows while trying to answer a critical question: are QM-based methods of real help in drug-design and -discovery research and industry?

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Calculation of Vibrational Frequencies by Molecular Mechanics

Cited by 2 publications

References 89 publications

In situ and Operando Raman Spectroscopy of Layered Transition Metal Oxides for Li-ion Battery Cathodes

In situ and Operando Raman Spectroscopy of Layered Transition Metal Oxides for Li-ion Battery Cathodes

Quantum mechanics implementation in drug-design workflows: does it really help?

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