Publications by authors named "K Szalewicz"
A dispersion-corrected density functional theory (DFT+D) method has been developed. It includes a nonhybrid dispersionless generalized gradient approximation (GGA) functional paired with a literature-parametrized dispersion function. The functional's 9 adjustable parameters were optimized using a training set of 589 benchmark interaction energies.
View Article and Find Full Text PDFCrystal structure predictions for molecules with soft degrees of freedom using intermonomer force fields derived from first principles.
Acta Crystallogr B Struct Sci Cryst Eng Mater
December 2024
Article Synopsis
- - The seventh blind test for molecular crystal structure prediction (CSP) involved two stages with seven diverse crystal targets, including cocrystals and a salt, analyzed using a CSP protocol that started with finding optimal molecule conformations.
- - An ab initio two-body rigid-monomer six-dimensional force field (aiFF) was developed to assist with packing and energy minimization in CSPs, incorporating flexible-monomer techniques for specific targets.
- - The results highlighted a success rate of 15% in structure generation and 33% in structure rating during the submission phase, improving significantly post-submission to 54% and 89%, respectively; the study suggests a conformer-based CSP approach is effective for crystals with flexible
The seventh blind test of crystal structure prediction: structure ranking methods.
Acta Crystallogr B Struct Sci Cryst Eng Mater
December 2024
Article Synopsis
- Participants from 22 research groups utilized various methods, including periodic DFT-D methods, machine learning models, and empirical force fields to assess crystal structures generated from standardized sets.
- The findings indicate that DFT-D methods generally aligned well with experimental results, while one machine learning approach showed significant promise; however, the need for more efficient research methods was emphasized due to resource consumption.
The seventh blind test of crystal structure prediction: structure generation methods.
Acta Crystallogr B Struct Sci Cryst Eng Mater
December 2024
A seventh blind test of crystal structure prediction was organized by the Cambridge Crystallographic Data Centre featuring seven target systems of varying complexity: a silicon and iodine-containing molecule, a copper coordination complex, a near-rigid molecule, a cocrystal, a polymorphic small agrochemical, a highly flexible polymorphic drug candidate, and a polymorphic morpholine salt. In this first of two parts focusing on structure generation methods, many crystal structure prediction (CSP) methods performed well for the small but flexible agrochemical compound, successfully reproducing the experimentally observed crystal structures, while few groups were successful for the systems of higher complexity. A powder X-ray diffraction (PXRD) assisted exercise demonstrated the use of CSP in successfully determining a crystal structure from a low-quality PXRD pattern.
View Article and Find Full Text PDFMeasurements of rovibrational spectra of clusters provide physical insight only if spectral lines can be assigned to pairs of quantum states, and further insight is obtained if one can deduce the quantitative energy-level pattern. Both steps can be so difficult that some measured spectra remain unassigned, one example is H-CO. To extend the scope of spectroscopic insights, we propose to use theoretical information in interpretation of spectra.
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