We combine atomistic simulation and experiment to study the mechanisms and processes involved in mechanically induced reactions in solids. We have particular interest in the role of phonon dynamics in dictating material mechanical response. Experimentally, our group makes extensive use of large scale international facilities including both synchrotrons and neutron sources.

We are particularly interested in understanding, at the atomic scale, how mechanical energy manifests into physical and chemical transformations in solid materials. In this area we make use of a range of atomistic simulation tools and develop new theoretical frameworks to describe mechanochemical reactions at the atomic level. In this area we have particular interest in understanding the role of material dynamics (lattice dynamics) in mechanochemical reactivity. To this end we are very interested in better understanding the dynamics of solids (see below).

A few of our recent papers include:

1. AAL Michalchuk. The Mechanochemical Excitation of Crystalline LiN3 Faraday Discuss. 2022

2. AAL Michalchuk and CA Morrison. From Lattice Vibrations to Molecular Dissociation, Theoretical and Computational Chemistry, 2021

3. AAL Michalchuk, M Trestman, S Rudic, P Portius, PT Fincham, CR Pulham, CA Morrison, Predicting the reactivity of energetic materials: an ab initio multi-phonon approach, J. Mater. Chem. A., 2019, 7, 19539-19553 

We are interested to learn how to selectively control reactivity in and between solids using mechanical force, including at high pressure conditions. In addition to detailed experimental studies in the laboratory, we actively develop experimental methods - typically based on synchrotron radiation such as X-ray diffraction and X-ray absorption spectroscopy - to follow mechanochemical reactions as they happen. Using these methods we obtain new insights into structural changes during ball milling to develop new mechanistic understanding of mechanochemical reactions. We also have interest in understanding the macroscopic kinetics of mechanochemical reactions as an additional tool to develop mechanistic understanding and learn to control these reactions.

A few of our recent papers include:

1. AAL Michalchuk, EV Boldyreva, AM Belenguer, F Emmerling, and VV Boldyrev, Tribochemistry, Mechanical Alloying, Mechanochemistry: What is in a Name? Front. Chem. 2021, 9, 685789

2. G Lampronti, AAL Michalchuk, PP Mazzeo, AM Belenguer, JKM Sanders, A Bacchi, and F Emmerling Changing the game of time resolved X-ray diffraction on the mechanochemistry playground by downsizing Nature Commun. 2021, 12, 6134

3. PMF de Oliveira, AAL Michalchuk, A Guilherme Buzanich, R Bienert, RM Torresi, PHC Camargo, and F Emmerling. Tandem X-ray absorption spectroscopy and scattering for in situ time-resolved monitoring of gold nanoparticle mechanosynthesis. Chem. Commun. 2021, 56, 10329-10332

4. AAL Michalchuk and F Emmerling. Time resolved in situ monitoring of mechanochemical reactions. Angew. Chem. Int. Ed. 2022, 61, e202117270

While most crystals are brittle, and therefore break when you try to bend them, a new class of single crystals have been found which bend rather easily. These materials open the door to an entirely new class of advanced functionality, including in energy harvesting, as sensors, or for flexible opto-electronic devices. However, we do not yet know how or why some crystals bend, while others do not. We are interested in exploring the atomistic origins of this phenomenal behaviour using the synergies of experiment and simulation in hopes to identify new strategies to selectively design these materials and pave the way to targeted design of next-generation materials.

A few of our recent papers include:

1. X Liu, AAL Michalchuk, B Bhattacharya, F Emmerling, and CR Pulham High-pressure reversibility in a plastically flexible coordination polymer crystal Nature Commun. 2021, 12, 3871

2. B Bhattacharya, AAL Michalchuk, D. Silbernagl, M Rautenberg, T Schmid, T Feiler, K Reimann, A Ghalgaoui, H Sturm, B Paulus, and F Emmerling A Mechanistic Perspective on Plastically Flexible Coordination Polymers Angew. Chem. Int. Ed. , 59, 5557-5561

3. B Bhattacharya, AAL Michalchuk, D Silbernagl, N Yasuda, T Feiler, H Sturm, and F Emmerling, An atomistic mechanism for elasto-plastic bending in molecular crystals Chem. Sci. 14, 3441-3450

Energetic materials (explosives, propellants, and pyrotechnics) release large amounts of energy when initiated by various stimuli such as mechanical impact and friction. Understanding how mechanical stimuli lead to energetic material initiation is an exceptional challenge, and holds the key to designing better and safer materials. We are developing new theoretical approaches to understand the mechanochemistry of energetic materials with the aim of establishing better fundamental insights into their reactivity. We are particularly interested in how material dynamics influence mechanochemical reactivity. Our theoretical developments are complemented closely by experimental studies including material response to extreme pressure and temperature.

A few of our recent papers include:

1. AAL Michalchuk, S Rudic, CR Pulham, and CA Morrison. Predicting the impact sensitivity of a polymorphic high explosive: the curious case of FOX-7 . Chem. Commun. 2021, 57, 11213-11216

2. AAL Michalchuk, J Hemingway, and CA Morrison. Predicting the impact sensitivities of energetic materials through zone-center phonon up-pumping . J. Chem. Phys. 2021, 154, 064105

3. S Konar, AAL Michalchuk, N Sen, CL Bull, CA Morrison, and CR Pulham. High-Pressure Study of Two Polymorphs of 2,4,6-Trinitrotoluene Using Neutron Powder Diffraction and Density Functional Theory Methods. J. Phys. Chem. C 2019, 123, 26095-26105

The structure and chemistry of solid materials is intimately related to their dynamical behaviour. We have therefore strong interests in better understanding this dynamical behaviour of solids, including under extreme conditions of temperature and pressure, in the hopes of better understanding (and ultimately controlling) material reactivity. In this area we have a strong focus on theoretical methods for studying lattice dynamics, and make extensive use of complementary experimental techniques such as inelastic neutron scattering spectroscopy (INS) and X-ray diffraction.

A few of our recent papers include:

1. T Aree, CJ McMonagle, AAL Michalchuk and D Chernyshov. Low-frequency lattice vibrations from atomic displacement parameters of α-FOX-7, a high energy density material. Acta. Cryst. B, 2022, 78, 376-384

2. B Zakharov, AAL Michalchuk, CA Morrison, and EV Boldyreva. Anisotropic lattice softening near the structural phase transition in the thermosalient crystal 1,2,4,5-tetrabromobenzene. Phys. Chem. Chem. Phys. 2018, 20, 8523-8532

3. X Liu, AAL Michalchuk, B Bhattacharya, F Emmerling, and CR Pulham High-pressure reversibility in a plastically flexible coordination polymer crystal Nature Commun. 2021, 12, 3871

4. AAL Michalchuk, M Trestman, S Rudic, P Portius, PT Fincham, CR Pulham, CA Morrison, Predicting the reactivity of energetic materials: an ab initio multi-phonon approach, J. Mater. Chem. A., 2019, 7, 19539-19553