Download First Principles Modeling of Molecular Crystals

First Principles Modeling of Molecular Crystals
Noa Marom
Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118
Molecular crystals are typically bound by weak dispersion interactions, which give rise to
shallow potential energy landscapes with many local minima. As a result, molecular crystals
often have several polymorphs that are very close in energy, but may possess markedly
different physical and chemical properties. The ability to predict the structure and energetics of
molecular crystal polymorphs is of paramount importance, particularly for the pharmaceutical
industry. Most drugs are marketed in the form of molecular crystals and obtaining the wrong
polymorph may be detrimental for the functionality of a drug.
Treating polymorphism within density functional theory (DFT) has been a long standing
problem because conventional exchange-correlation functionals lack a proper description of
dispersion interactions. Pairwise C6/R6 dispersion corrections have significantly advanced the
field [1, 2] and often yield useful qualitative results when the energy differences are sufficiently
large [3, 4], for example, in the case of the pseudo-polymorphism of the malaria pigment,
hemozoin [5, 6]. However, these methods cannot reach the desired “chemical accuracy” of 0.1
kcal/mol.
Recently, a new method has been developed to account for long-range electrostatic screening
and for many-body dispersion (MBD) interactions [7]. Accounting for the long-range
electrostatic screening in extended systems is essential for obtaining the correct dielectric
constants and ensuing optical properties of molecular crystals [8]. Accounting for the nonadditive many-body dispersion interactions is crucial for obtaining a highly accurate description
of the energetics of molecular crystals, including lattice energies, sublimation enthalpies, and
relative stabilities of polymorphs [8, 9].
References:
[1] N. Marom, A. Tkatchenko, M. Scheffler, L. Kronik, J. Chem. Theory Comput. 6, 81 (2010)
[2] N. Marom, A. Tkatchenko, M. Rossi, V. V. Gobre, O. Hod, M. Scheffler, L. Kronik, J. Chem. Theory Comput. 7,
3944 (2011)
[3] N. Marom, J. Bernstein, J. Garel, A. Tkatchenko, E. Joselevich, L. Kronik, O. Hod, PRL 105, 046801 (2010)
[4] N. Marom, J. E. Moussa, X. Ren, A. Tkatchenko, J. R. Chelikowsky, PRB 84, 245115 (2011)
[5] N. Marom, A. Tkatchenko, S. Kapishnikov, L. Kronik, L. Leiserowitz, Crystal Growth & Design 11, 3332 (2011)
[6] T. Straasø, N. Marom, I. Solomonov, L. K. Barfod, M. Burghammer, R. Feidenhans’l, J. Als-Nielsen, L. Leiserowitz,
submitted to Crystal Growth & Design
[7] A. Tkatchenko, R. A. DiStasio, Jr., R. Car, M. Scheffler, Phys. Rev. Lett. 108, 236402 (2012)
[8] B. Schatschneider, J. Liang, A. M. Reilly, N. Marom, G. Zhang, A. Tkatchenko, Phys. Rev. B 87, 060104(R) (2013)
[9] N. Marom, R. A. DiStasio, Jr. , V. Atalla, S. Levchenko, A.M. Reilly, J. R. Chelikowsky, L. Leiserowitz, A.
Tkatchenko, Angew. Chem. Int. Ed. 125, 6761 (2013)