Structure and intermolecular potentials in molecular crystals

Gavezzotti, Angelo

doi:10.1088/0965-0393/10/3/201

Cited by 63 publications

(54 citation statements)

References 76 publications

(67 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Current methods of carrying out calculations on molecular crystals 28 frequently use free molecule structures and parameters, such as charge densities, in order to simulate the crystal, i.e., a free molecule is placed in the field due to the other molecules within the unit cell and then a calculation is carried out: the above raises serious issues about the validity of such an approach, for clearly it is inappropriate to assume that the molecule does not relax its internal degrees of freedom in the solid state. This is in agreement with the work of Puschnig and co-workers, who have discussed the importance of treating the full three-dimensional symmetry of the crystal in such calculations.…”

Section: Structural Propertiesmentioning

confidence: 99%

Structural and electronic properties of L-amino acids

Tulip

Clark

2005

Phys. Rev. B

View full text Add to dashboard Cite

The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. The structural and electronic properties of four L-amino acids alanine, leucine, isoleucine, and valine have been investigated using density functional theory ͑DFT͒ and the generalized gradient approximation. Within the crystals, it is found that the constituent molecules adopt zwitterionic configurations, in agreement with experimental work. Lattice constants are found to be in good agreement with experimentally determined values, although certain discrepancies do exist due to the description of van der Waals interactions. We find that these materials possess wide DFT band gaps in the region of 5 eV, with electrons highly localized to the constituent molecules. It is found that the main mechanisms behind crystal formation are dipolar interactions and hydrogen bonding of a primarily electrostatic character, in agreement with current biochemical understanding of these systems. The electronic structure suggests that the amine and carboxy functional groups are dominant in determining band structure.

show abstract

Section: Structural Propertiesmentioning

confidence: 99%

Structural and electronic properties of L-amino acids

Tulip

Clark

2005

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…For the first, we calculate the lattice parameters for crystals of the cagelike hexamine, dodecahedrane, and cubane molecules. For the second, we compare an atom-centered asymptotic-1 / r 6 approximation frequently encountered in force-field methods 6,30,31 and in DFT-D, with the correlation energy provided by vdW-DF. We also analyze consequences for DFT-D and question its performance at intermediate separations.…”

Section: Introductionmentioning

confidence: 99%

Structure and binding in crystals of cagelike molecules: Hexamine and platonic hydrocarbons

Berland

Hyldgaard

2010

The Journal of Chemical Physics

View full text Add to dashboard Cite

In this paper, we show that first-principle calculations using a van der Waals density functional ͑vdW-DF͒ ͓M. Dion, H. Rydberg, E. Schröder, D. C. Langreth, and B. I. Lundqvist, Phys. Rev. Lett. 92, 246401 ͑2004͔͒ permit the determination of molecular crystal structure within density functional theory ͑DFT͒. We study the crystal structures of hexamine and the platonic hydrocarbons ͑cubane and dodecahedrane͒. The calculated lattice parameters and cohesion energy agree well with experiments. Further, we examine the asymptotic accounts of the van der Waals forces by comparing full vdW-DF with asymptotic atom-based pair potentials extracted from vdW-DF. The character of the binding differs in the two cases, with vdW-DF giving a significant enhancement at intermediate and relevant binding separations. We analyze consequences of this result for methods such as DFT-D and question DFT-D's transferability over the full range of separations.

show abstract

“…Force fields can be more or less generic. With access to experimental data it is possible to develop tailor-made, adhoc force fields, specially parameterized for one or a few molecules, which can be remarkably successful, but limited in use [32]. For most calculations, however, there are generic force fields available.…”

Section: Force Fields Parameterization and Evaluationmentioning

confidence: 99%

Crystal Structure Prediction in the Context of Pharmaceutical Polymorph Screening and Putative Polymorphs of Ciprofloxacin

Singh

Chadha

2017

Int J Pharm Pharm Sci

View full text Add to dashboard Cite

Molecular simulation is increasingly used by medicinal chemists in the process and product development. Reliable computational predictions are of great value not only for the design of an active pharmaceutical ingredient with novel properties but also for the avoidance of an undesirable change of form in the late stages of development of an industrially important molecule. In the pharmaceutical industry, drug polymorphism can be a critical problem and is the subject of various regulatory considerations. This contribution tried to review the fuzzy frontiers between the chemical structure of the molecule and its crystal energy landscape with a particular focus on the crystal structure prediction (CSP) methodology to complement polymorph screening. A detailed application of CSP in the pharmaceutical industry is illustrated on ciprofloxacin; describing its putative polymorphs. This approach successfully identifies the known crystal form within this class, as well as a large number of other low-energy structures. The performance of the approach is discussed in terms of both the quality of the results and computational aspects. CSP methods are now being used as part of the interdisciplinary range of studies to establish the range of solid forms of a molecule. Moreover, further methodological improvements aimed at increasing the accuracy of the predictions and at broadening the range of molecules i.e. co-crystals, salts and solvates.

show abstract

Structure and intermolecular potentials in molecular crystals

Cited by 63 publications

References 76 publications

Structural and electronic properties of L-amino acids

Structural and electronic properties of L-amino acids

Structure and binding in crystals of cagelike molecules: Hexamine and platonic hydrocarbons

Crystal Structure Prediction in the Context of Pharmaceutical Polymorph Screening and Putative Polymorphs of Ciprofloxacin

Contact Info

Product

Resources

About