Rachel Crespo Otero

Machine learning for nonadiabatic molecular dynamics: best practices and recent progress Exploring molecular excited states holds immense significance across organic chemistry, chemical biology, and materials science. Understanding the photophysical properties of molecular chromophores is...

Check out our new collaborative paper on machine learning for nonadiabatic molecular dynamics published in @chemicalscience.rsc.org. It provides an overview of the current state-of-the-art and best practices. Thx to
@jwestermayr.bsky.social @stevenalopez.bsky.social @rcrespootero.bsky.social ...

Thanks to Marcus Brady for the hard work!

Is MRSF-TDDFT Suitable for Cyclobutanone Dynamics? The Role of Higher Energy States in Surface Hopping Simulations Modelling photochemical reactions remains a significant challenge due to the need for accurate descriptions of multiple excited states and their couplings with nuclear vibrations. Despite considerable...

Inspired by the Cyclobutanone Photochemistry Challenge, we assessed MRSF-TDDFT for its excited-state dynamics and found that an S₃/S₂ conical intersection likely plays a key role in the photochemistry. Take a look at our new preprint: chemrxiv.org/engage/chemr...

Describing Excited States of Covalently Connected Crystals with Cluster and Embedded Cluster Approaches: Challenges and Solutions Understanding excited-state processes is essential for designing new functional organic materials. Modeling excited states in organic crystals is challenging due to the need to balance localized and delocalized processes and the competition between intramolecular and intermolecular interactions. Cluster models have proven highly effective for describing weakly interacting organic crystals; however, nonperiodic calculations on periodic systems must account for mechanical and electrostatic coupling to the crystal lattice, particularly in cases of extended coordination where covalent bonds are severed, such as in organic polymers and metal–organic frameworks (MOFs). Point charge embedding is a low-cost method for incorporating long-range electrostatics, enabling the consideration of long-range interactions using Ewald embedding. Small clusters have been effective for modeling excited-state processes in MOFs, yet embedding has rarely been included in such studies. In this work, we examine some of the challenges in describing excited states in covalently connected organic crystals using ONIOM(QM:QM’) embedding techniques across systems with increasing coordination: diC4–BTBT (an organic molecular crystal), polythiophene (an organic polymer), and two MOFs (QMOF-d29cec2 and MOF-5). We analyze the effects of using different electronic structure methods, including TDHF, TDDFT, ADC(2), and CC(2). One of the main challenges is that embedded cluster models are susceptible to overpolarization near the QM:QM’ boundary. To address this, we assess the impact of different charge redistribution schemes (Z-N (N = 0, 3), RC, and RCD) and implement them in fromage. Additionally, we compare cluster and periodic models. We find that localized models effectively reproduce excited states in both nonconnected systems (diC4–BTBT) and fully connected MOFs, whereas polythiophene remains the most challenging due to band conduction. The accuracy of vertical excitations, oscillator strengths, and simulated spectra is strongly influenced by model size, boundary charges, redistribution schemes, and level of theory. We further analyze the effect of vibrational broadening using the nuclear ensemble approach to predict the absorption and emission spectra of MOF-5. Our results provide a heuristic guide for nonperiodic studies of crystalline excited states, highlighting the remarkable relationship between molecular crystals and MOFs, which will be explored in the future work.

pubs.acs.org/doi/10.1021/...
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A couple of papers from the group are finally out in JCTC and PCCP! We can do excited states in MOFs with fromage now! We looked at the dual emission in terephthalic and isophthalic acid crystals. Thanks to the wonderful work of Michael Ingham, Marcus, Ljiljana, and Michael Dommett

Describing excited states of covalently connected crystals with cluster and embedded cluster approaches: Challenges and solutions Understanding excited-state processes is essential for designing new functional organic materials. Modelling excited states in organic crystals is challenging due to the need to balance localised and ...

Our most recent preprint on modelling excited states in covalently connected crystals like MOFs and organic polymers can be found in ChemRxiv. Thanks to Michael Ingham for the hard work. go.shr.lc/44mefar

Origins of crystallisation-induced dual emission of terephthalic and isophthalic acid crystals Metal-free organic crystals with room-temperature phosphorescence (RTP) present an innovative alternative to conventional inorganic materials for optoelectronic applications and sensing. Recently, sub...

Very happy about this preprint from the group! In this paper, we analysed the excited states and dual emission in terephthalic and isophthalic acid crystals. Many thanks to Ljiljana for the excellent work and to Michael Dommett, who initiated this project! :-) chemrxiv.org/engage/chemr...

Are you using nonadiabatic dynamics for complex systems? Join us in sunny Spain for the "Future Directions in Non-Adiabatic Dynamics" workshop (Sept 2-5, 2025) at CECAM-Zaragoza! Register by June 3. Check out the event page: tinyurl.com/2nvnanf2

#NAMD #NonAdiabaticDynamics #CECAM

Less than two weeks left to register for the 2025 CECAM Flagship school in computational photochemistry: shorturl.at/xsbEa with lectures from Basile Curchod, Javier Segarra, Javier Cerezo, Roger Bello and myself. Please spread the word!
#compchem #compchemsky

Machine learning photodynamics decode multiple singlet fission channels in pentacene crystal - Nature Communications Singlet fission enables high light-harvesting abilities in pentacene crystals. Here the authors use machine-learning photodynamics to show competing charge-transfer-mediated and coherent mechanisms dr...

I am very happy to see our paper on SF fission in pentacene crystals using ML-accelerated NAD finally published in Nat. Comm.!(nature.com/articles/s41...).
Many thanks to our fantastic team: @jingbai-li.bsky.social, Fede Hernandez, @stevenalopez.bsky.social, Christian, and the RS for funding!

Now a paper in J. Phys. Chem. C pubs.acs.org/doi/10.1021/..., our contribution to the Francesc Illas and Gianfranco Pacchioni Festschrift. #compchemsky (1/n)

A 3-Year PhD Studentship in Data-driven analysis of excited states in metal-organic frameworks at University College London on FindAPhD.com PhD Project - A 3-Year PhD Studentship in Data-driven analysis of excited states in metal-organic frameworks at University College London, listed on FindAPhD.com

I have a PhD scholarship (UCL-A*STAR) in "Data-driven analysis of excited states in metal-organic frameworks". This is a collaboration with @mbsullivan.bsky.social. See the details of the scholarship following this link: www.findaphd.com/phds/project...

A starter pack on the molecular theoretical quantum world.

#compchem #molphys #theochem 🧪

go.bsky.app/UGFPoE2