Quantum chemical and molecular dynamics study of advanced solids and nanomaterials: challenging road to reality
Project leader Dmitry Bocharov
Agreement No 126.96.36.199/16/I/001
Research application No 188.8.131.52/VIAA/1/16/147
The aim of this project is to develop new efficient simulation strategy for describing dynamics and anisotropic vibrational properties of advanced materials as well as chemical re-bonding and defect redistribution in complex technologically important crystals and nanomaterials. For these simulations, both density functional theory (DFT) and ab initio molecular dynamics (AIMD) have been applied. The limits of applicability of existing methods and transferability of the results obtained for regular bulk properties will be estimated on defective and low-dimensional materials. The accuracy of AIMD simulations will be validated by a direct comparison with the available temperature-dependent X-ray absorption spectra. The developed new strategy and large-scale massive parallel computer simulations will be applied for calculations on photocatalytic properties of nanostructures (nanowires, nanotubes, nanoclusters) including the calculations of the excited states and simulations of water adsorption and dissociation on photocatalyst surface for detailed understanding of the photodissociation mechanisms. The project is multidisciplinary and combines materials science, solid state chemistry, physics and computer science.
The total duration of the project is 36 months, the total cost is 133,805.88 EUR.
August 15, 2019
From April 29 until May 12, there was mobility to Paul Sherrer Institute, Switzerland. During the mobility, the results of the ScF3, MoS2 and WS2 calculations were discussed as well as well as ZnO2 compound calculations were started. The calculations and the analysis of the results of these compounds continued in the following months.
A paper D. Bocharov, M. Krack, Yu. Rafalskij, A. Kuzmin, and J. Purans «Ab initio molecular dynamics simulations of negative thermal expansion in ScF3: the eﬀect of the supercell size» was finished and submitted to the journal Computational Material Science in May. Additional ScF3 calculations were performed and text partial rewriting for this article were made following reviewer's comments.
Starting from May 25 until June 1, project leader attended the 2019 EMRS Spring Meeting Conference (Nice, France). Two poster presentations “First-principles molecular dynamics simulations of layered WS2 materials” and “Ab initio molecular dynamics calculations of ScF3 temperature dependent structural properties” were presented, as well as contacts with prof. Ivano Castelli (Technical University of Denmark) were established.
On May 23 project leader participated in Radio Baltcom broadcast about Latvian Science Prospects, mentioned also a post-doctoral program in Latvia youtu.be/r2edN1PQ6XU
JIn July, a two-dimensional model of Cu3N was constructed for the study of the Cu3N / Cu + N2 chemical decomposition process.
From June 26 until July 9 in the frames of mobility the University of Duisburg-Essen was visited. The draft version of the paper „Validation of 2D constrained models for TiO2 nanotubes over a broad range of diameters” was updated and partially rewritten. Assess to Essen-Duisburg computer cluster was organized as well as common activities in framework of the post-doctoral project 184.108.40.206/VIAA/l/16/147 were discussed.
On July 25, project manager participated in a radio Baltcom program about quantum physics: https://youtu.be/d7DjSugMdLA
May 17, 2019
In November-April ab initio molecular dynamics calculations of WS2 and MoS2 compounds were performed.
The manuscript of the Dmitry Bocharov, Janis Timoshenko, Andris Anspoks, Aleksandr Kalinko, Alexei Kuzmin, Matthias Krack, “Interpretation of the Cu K-edge EXAFS spectra of Cu3N using ab initio molecular dynamics” was updated after reviewers comments and returned to the journal “Radiation Physics and Chemistry”. This paper was accepted for publication (https://doi.org/10.1016/j.radphyschem.2018.12.020).
The paper D. Bocharov, M. Krack, Yu. Rafalskij, A. Kuzmin, J. Purans, “Ab initio molecular dynamics calculations of ScF3 temperature dependent structural properties” was preparing for submission to “Computational Materials Science” journal.
During the mobility to Paul Scherrer partner organization in January-February analysis of calculated data for ScF3 was performed. The preparation of the manuscript P. Žguns, D. Bocharov, S. Piskunov, A. Kuzmin, J. Purans, „Quantum chemistry calculations on ScF3 lattice dynamics” was started.
The oral talk D. Bocharov, J. Timoshenko, A. Anspoks, A. Kalinko, A. Kuzmin, M. Krack. "Ab initio molecular dynamics calculations of Cu3N temperature dependent structural properties" was given at annual ISSP UL conference in February.
March 9-17 post-doctoral fellow participated in 53rd Russian School on Condensed State Physics (St. Petersburg nuclear institute). The poster Dmitry Bocharov, Janis Timoshenko, Andris Anspoks, Aleksandr Kalinko, Alexei Kuzmin, Matthias Krack, „Ab initio molecular dynamics calculations of Cu3N temperature dependent structural properties” was presented.
March 18-27 in the frames of mobility the University of Duisburg-Essen was visited. During a business trip the results of TiO2 calculations were discussed with Prof. E. Spohr, a plan for the “Validation of 2D constrained models for TiO2 nanotubes over a broad range of diameters” was prepared; as well the cooperation in the framework of project 220.127.116.11/VIAA/l/16/147 was discussed.
From April 08 until April 12, there was mobility to Paul Sherrer Institute, Switzerland. During the mobility, the results of the ScF3 and WS2 calculations were discussed, as well as CP2K software installation on LASC and MARCONI supercomputers was completed.
On April,17 during the campaign "Back to School / Back to University 2019" D.Bocharov visited to J.G. Herder's Riga Grizinkalns Secondary School, where he discussed science topics and EU projects with 65 students from 3 forms.
The paper Dmitry Bocharov, Yuri Rafalskij, Matthias Krack, Mara Putnina and Alexei Kuzmin, Negative thermal expansion of ScF3: first principles vs empirical molecular dynamics. IOP Conf. Ser.: Mater. Sci. Eng. 503 (2019) 012001 was published.
November 05, 2018
An article was published in July: D. Bocharov, S. Piskunov, Yu.F. Zhukovskii, and R.A. Evarestov. Ab initio calculations on the electronic structure and photocatalytic properties of two-dimensional WS2 (0001) nanolayers of varying thickness. Phys. Status Solidi RRL, 2018, 12, 1800253 (pp. 1-6). DOI: 10.1002/pssr.201800253, SNIP(2017)=1.017, IF(2017)=3.721. In this study we have performed hybrid DFT-LCAO calculations of WS2 nanosheets possessing stable 2H c hexagonal phase with thickness between 1 and 40 monolayers (ML) using hybrid exchange-correlation functional HSE06 adopted for this purpose. Defect less pristine WS2 nanosheets have been found to be suitable for photocatalytic applications since widths of their band gaps correspond to the range of visible light between the red and violet edges, while the top of the valence band and the bottom of the conduction band are properly aligned relative to the oxidation and reduction potentials. We found that the band gap of nanolayers decreases with growing the number of MLs in layered WS2 2D structure. The highest solar energy conversion efficiency (15–18%) usually achieved for band gap 2.0–2.2 eV (yellow range of the visible spectrum) has been found for the 2 ML thick stoichiometric WS2 (0001) nanosheet. WS2 nanolayers as prospective material for photocatalysis demand no doping or formation of vacancies as in the case of nanostructures of transition metal oxides.
From 07/21/2018 until 07/27/2018, principal investigator visited Krakow, Poland, where attended the XAFS 2018 conference. Two presentations were arranged: “Interpretation of the Cu K-edge EXAFS spectra of Cu3N using ab initio molecular dynamics” (oral presentation)) and “Validation of ab initio molecular dynamics simulations of ZnO using the Zn K-edge EXAFS spectra” (poster).
From 10/02/2018. until 10/05/2018, principal investigator attended International conference “Functional Materials & Nanotechnology” (FM&NT) held in Riga. Latvia. Poster was presented: Dmitry Bocharov, Yuri Rafalskij, Matthias Krack, Mara Putnina and Alexei Kuzmin, Negative thermal expansion of ScF3: first principles vs empirical molecular dynamics“.
In July - October, two articles were finalized and submitted for review: Dmitry Bocharov, Janis Timoshenko, Andris Anspoks, Aleksandr Kalinko, Alexei Kuzmin, Matthias Krack, “Interpretation of the Cu K-edge EXAFS spectra of Cu3N using ab initio molecular dynamics” (“Radiation Physics and Chemistry”) un Dmitry Bocharov, Yuri Rafalskij, Matthias Krack, Mara Putnina and Alexei Kuzmin, Negative thermal expansion of ScF3: first principles vs empirical molecular dynamics“ (“IOP Conference Series: Materials Science and Engineering”).
July 13, 2018
During the first three months of the project systematic calculations of Cu3N and ZnO were performed using ab initio molecular dynamics in CP2K code framework. The test DFT and ab initio molecular dynamics calculations of WS2 and MoS2 bulk was performed for the project "First-principle molecular dynamics simulations of layered WS2 and MoS2 materials ". This project was submitted together with Swiss partner Dr. M. Krack (Paul Scherrer Institute) for CSCS Swiss supercomputer spring call (results of the project estimation will be announced in September 2018).
DFT atomic and electronic structure calculations of WS2 bulk and nanolayered structures were performed using the CRYSTAL14 software and the LCAO method. The article "D. Bocharov, S. Piskunov, Yu.F. Zhukovskii, R.A. Evarestov, Ab initio calculations on the electronic structure and photocatalytic properties of two-dimensional WS2 (0001) nanolayers of varying thickness" was written and submitted for review to the journal "Physica status solidi".
From May 13, 2018 to May 18, 2018 the author of the project participated in a scientific meeting on the photocatalytic processes in solids, nanostructures and nanotubes in Moscow (N.S. Kurnakov Institute of General and Inorganic Chemistry). During the meeting, the synergy between the project WATERSPLIT and the post-doctoral project 18.104.22.168/VIAA/l/16/147 was discussed with partner E. Spohr (The University of Duisburg-Essen).
From June 25, 2018 to July 3, 2018 first mobility took place at the Paul Scherer Institute, Switzerland. During the mobility with Swiss partner Dr. M. Krack were discussed the results of calculations for ScF3, Cu3N, UO2 and ZnO compounds, as well as discussed collaboration on first project stage.
On April 5, the project author participated in Latvian Radio 4 radio popular science broadcast http://lr4.lsm.lv/lv/raksts/priroda-veschey/smena-paradigmi-sovremennoy-latviyskoy-nauki-teorija-i-praktika.a101981/: