Estimation of Lattice Energies of Organic Molecular Crystals by Combination of Experimentally Determined and Quantum- Chemically Calculated Quantities: A New Value for the Lattice Energy of a-Glycine

1999 ◽  
Vol 54 (10-11) ◽  
pp. 611-616 ◽  
Author(s):  
Gerhard Raabe
Keyword(s):  
Total Energy ◽  
Ab Initio ◽  
Gas Phase ◽  
Molecular Crystals ◽  
Lattice Energy ◽  
Energy Difference ◽  
Crystalline Form ◽  
Stable Form ◽  
Organic Molecular Crystals ◽  
Ab Initio Theory

A new value for the lattice energy of a-glycine was determined by combination of the experimentally measured heat of sublimation taken from literature and the quantum-chemically calculated energy difference Etot,gp - Etot,cry, where Etot,gp is the total energy of the most stable form of the compound in the gas phase (carboxylic acid) and Etot,cry the total energy of the molecule as it occurs in its crystalline form (betaine). At the highest levels of ab initio theory employed in this study this energy difference is -(28±2) kcal/mol, indicating that older work overestimated this difference significantly. The reason for the overestimation of this energy difference was determined by means of additional ab initio calculations. The lattice energy of -(67±2)kcal/mol obtained using the new value for Etot,gp - Etot,cry is significantly more positive than an older value of -103 kcal/mol frequently cited in the literature.

Computational Procedure of Lattice Energy Using the Ab Initio MO Method

2003 ◽  
Vol 02 (02) ◽  
pp. 233-244 ◽  
Author(s):  
Kanade Nagayoshi ◽  
Tohru Ikeda ◽  
Kazuo Kitaura ◽  
Shigeru Nagase
Keyword(s):  
Ab Initio ◽  
Molecular Crystals ◽  
Lattice Energy ◽  
Computational Procedure ◽  
Basis Set ◽  
Full Account ◽  
Packing Structure ◽  
Donor Acceptor ◽  
Ab Initio Mo ◽  
Experimental Values

Recently, we have proposed a computational procedure for calculations of lattice energies of molecular crystals using the ab initio MO method. This procedure does not use potential functions and is applicable to a variety of molecular crystals. The procedure has been successfully applied to calculation of packing structure of electron donor-acceptor complex, H3N–BF3, and hydrogen bonding crystal, CH3OH. In this work, we present a full account of the computational procedure. This method is applied to the packing structure calculations of hydrocarbon crystals, C2H2, C2H4 and C6H6. The lattice parameters optimized at the MP2/6-311++G** level are in good agreement with the experimental values. The basis set dependence of the lattice constants is also discussed for several crystals.

Towards reliable ab initio sublimation pressures for organic molecular crystals – are we there yet?

2019 ◽  
Vol 21 (27) ◽  
pp. 14799-14810 ◽  
Author(s):  
Ctirad Červinka ◽  
Gregory J. O. Beran
Keyword(s):  
Ab Initio ◽  
State Of The Art ◽  
Molecular Crystals ◽  
Organic Molecular Crystals ◽  
Empirical Estimates

State-of-the-art ab initio predictions of sublimation pressures, matching experiment to a factor of 2–10, outperform the reliability of empirical estimates.

scholarly journals Accurate force fields and methods for modelling organic molecular crystals at finite temperatures

2016 ◽  
Vol 18 (23) ◽  
pp. 15828-15837 ◽  
Author(s):  
Jonas Nyman ◽  
Orla Sheehan Pundyke ◽  
Graeme M. Day
Keyword(s):  
Free Energy ◽  
Force Fields ◽  
Molecular Crystals ◽  
Lattice Energy ◽  
Organic Crystals ◽  
Organic Molecular Crystals ◽  
Energy Modelling

We assess a series of atom–atom force fields for lattice energy and free energy modelling of molecular organic crystals.

scholarly journals The Use of Quantum Chemical Semiempirical Methods to Calculate the Lattice Energies of Organic Molecular Crystals. Part I: The Three Polymorphs of Glycine

2000 ◽  
Vol 55 (6-7) ◽  
pp. 609-615 ◽  
Author(s):  
Gerhard Raabe
Keyword(s):  
Quantum Chemical ◽  
Chemical Method ◽  
Molecular Crystals ◽  
Lattice Energy ◽  
Potential Method ◽  
Electrostatic Energy ◽  
Semiempirical Methods ◽  
Quantum Chemical Method ◽  
Organic Molecular Crystals ◽  
Lattice Energies

Abstract A method to calculate the lattice energies of organic molecular crystals is described. It is based on the semiempirical quantum chemical MINDO/3 approximation but might also be used within the framework of any other quantum chemical method. The lattice energy is approximated by the sum of dispersion-, induction-, exchange repulsion-, and electrostatic energy. Different, however, from other schemes employed in this field, like for example the atom-atom-potential method, the variables in the expression for the lattice energy have not been fitted to reproduce experimental values and, therefore, the single contributions retain their original physical meaning. Moreover, the method offers the advantage that it may be directly applied to all compounds that can be treated within the framework of the underlying quantum chemical method. Thus, time consuming readjustment of the entire parameter set upon extension of the group of target molecules by another class of compounds becomes obsolete. As an example, the lattice energies of the three polymorphs of glycine are calculated.

scholarly journals The Use of Quantum-Chemical Semiempirical Methods to Calculate the Lattice Energies of Organic Molecular Crystals. Part III: The Lattice Energy of Borazine (B3N3H6) and its Packing in the Solid State*

2004 ◽  
Vol 59 (9) ◽  
pp. 609-614 ◽  
Author(s):  
Gerhard Raabe
Keyword(s):  
Quantum Chemical ◽  
Lattice Energy ◽  
Low Pressure ◽  
Semiempirical Methods ◽  
Dispersion Energy ◽  
Organic Molecular Crystals ◽  
Ab Initio Theory ◽  
Lower Melting Point ◽  
Chemical Scheme ◽  
Lattice Energies

A previously presented quantum-chemical scheme has been used to calculate the lattice energies of borazine (B3N3H6), the low pressure polymorph of benzene (C6H6), and of borazine in the lowpressure benzene lattice utilizing some frequently used semiempirical methods (CNDO/2, INDO, MINDO/3, MNDO, AM1, PM3, MSINDO). With all methods the lattice energy of the title compound was found to be less favourable than that of isoelectronic benzene, which offers an explanation of the significantly lower melting point of B3N3H6. Calculation of the lattice energy of borazine in the crystal lattice of the low-pressure modification of benzene revealed that the interactions between the molecules in this environment are not so stabilizing as those in its own lattice. This is predominantly due to a less favourable contribution of the dispersion energy. The semiempirical results have qualitatively been confirmed by quantum-chemical calculations on small molecular clusters at the MP2/6-31+G*//HF/6-31+G* level of ab initio theory. In these calculations we assumed pairwise additivity of the intermolecular interactions and calculated the energy of interaction between a reference molecule and all those neighbours to which the shortest intermolecular distance does not exceed 3Å.

scholarly journals The Use of Quantum-Chemical Semiempirical Methods to Calculate the Lattice Energies of Organic Molecular Crystals. Part II: The Lattice Energies of α- and β-Oxalic Acid (COOH)2

2002 ◽  
Vol 57 (12) ◽  
pp. 961-966 ◽  
Author(s):  
Gerhard Raabe
Keyword(s):  
Oxalic Acid ◽  
Quantum Chemical ◽  
Lattice Energy ◽  
Energy Difference ◽  
Electrostatic Energy ◽  
Semiempirical Methods ◽  
Stable Form ◽  
Crystal Lattices ◽  
Lattice Energies ◽  
Chemical Procedure

The lattice energies (ΔE lat) of α- and β-oxalic acid ((COOH)2) have been calculated using a recently introduced semiempirical quantum-chemical procedure. Within the framework of this method the lattice energy (ΔE lat) is evaluated as the sum of the semiempirically calculated intermolecular dispersion (ΔEdis), induction (ΔEind), repulsion (ΔErep), and electrostatic energy (ΔEels). The lattice energies of the two polymorphs of oxalic acid obtained in this way correlate not only with the results of other calculations but also with the experimentally determined heats of sublimation in that the α-modification, which has a somewhat higher heat of sublimation, is slightly more stable than the β-polymorph. However, additional quantum-chemical calculations at the non-empirical ab initio level (e. g. ZPE+MP2(FC)/6-311++G**//MP2(FC)/6-311++G**) revealed that the absolute values of the lattice energies and the heats of sublimation are not directly comparable to each other because the structures of the (COOH)2 molecules in the crystal lattices of both polymorphs differ significantly from that of the most stable form of the free molecule in the gasphase. At about 4.3 kcal/mol the calculated energy difference between the structure of the molecule in the solid state and the energetically most favourable conformation of the free (COOH)2 molecule in the gasphase is much smaller than that in the recently described case of α-glycine (28±2 kcal/mol). However, even such a small difference might be the source of serious problems if the heats of sublimation are employed to fit parameters to be used in the optimization of crystal packings.

scholarly journals Repulsion–dispersion parameters for the modelling of organic molecular crystals containing N, O, S and Cl

2018 ◽  
Vol 211 ◽  
pp. 297-323 ◽  
Author(s):  
Christina A. Gatsiou ◽  
Claire S. Adjiman ◽  
Constantinos C. Pantelides
Keyword(s):  
Ab Initio ◽  
Molecular Crystals ◽  
Dispersion Parameters ◽  
Organic Molecular Crystals

A method for deriving parameters of atom–atom repulsion dispersion potentials for crystals, tailored to different ab initio models, is presented. It leads to a significant improvement in the accuracy of computed sublimation energies.

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