Atomistic dynamics in gas and condensed phases: theoretical and computational

Computational simulations and method development for understanding thermally- and light- activated or driven processes in molecular systems (current emphasis on plasmonic nanostructures and porous materials).

On the practical, technological side, I am interested in developing computational methods and strategies for extensive simulations over time and with large system sizes, with the focus on in-silica design and optimisation of nanostructures for diferent relevant purposes.
Amongst the systems and phenomena I have studied are reactive collisions of few-body systems, silicon-silicon oxide interfaces, photo-induced processes in molecular solids, first principle calculations of transport properties for pure gases and mixtures at very low pressure within the framework of kinetic theory. I have also worked on the modeling and simulation of plasmonic nanostructures upon irradiation with laser pulses. In the case of the latter, I am particularly interested in the optimisation and control of plasmonic nanostructures for the design in energy and biomedical applications. At the moment, I am also carrying out simulations of porous materials (MoF) in order to improve their response at high temperatures.
The tools I have used include: classical molecular dynamics, Monte Carlo methods (simple, importance-sampling, Metropolis, for path integrals, for rovibrational sampling, etc), hyperspherical coordinates, ab initio calculations of intra- and intermolecular potential energy surfaces (PES) (ground and excited states of few-atom molecules), analytical representation of PESs using reproducing kernel Hilbert space (RKHS) interpolation or Legendre polynomials, EAM potentials, three-atoms potentials, parallel computing, etc.
I have used a number of professional softwares such as: CHARMM, Gaussian, MOLPRO, ORCA, TRAJECT and LAMMPS. I commonly use FORTRAN as programming language and to a lesser extent C++, R and PYTHON.

Selected publications

More on my Publons

Hollow Gold Nanoparticles Produced by Femtosecond Laser Irradiation
J. C. Castro-Palacio, K. Ladutenko, A. Prada, G. González-Rubio, P. Díaz-Núñez, A. Guerrero-Martínez, P. Fernández de Córdoba, J. Kohanoff, J. M. Perlado, O. Peña-Rodríguez, and A. Rivera, J. Phys. Chem. Lett. 2020, 11, 5108-5114.
https://pubs.acs.org/doi/abs/10.1021/acs.jpclett.0c01233

Classical molecular dynamics simulations have been used to investigate the solid-to-hollow conversion of gold nanoparticles upon femtosecond laser irradiation. We describe the experimental conditions for efficiently producing hollow nanoparticles, opening a broad range of possibilities for applications in key areas,
such as energy storage and catalysis.

Fluctuations in measured radioactive decay rates inside a modified Faraday cage: Correlations with space weather
V. Milián-Sánchez, F. Scholkmann, P. Fernández de Córdoba, A. Mocholí-Salcedo, F. Mocholí, C. Milián, J. C. Castro-
Palacio, V. A. Kolombet, and G. Verdú, , Scientific Reports 10, 8525 (2020).
https://www.nature.com/articles/s41598-020-64497-0

Formation of Hollow Gold Nanocrystals by Nanosecond Laser Irradiation
G. González-Rubio, T. Milagres de Oliveira, W. Albrecht, P. Díaz-Núñez, J. C. Castro-Palacio, A. Prada, R. I. Gonzalez, L. Scarabelli, L. Banares, A. Rivera, L. M. Liz-Marzán, O. Peña-Rodríguez, S. Bals, and A. Guerrero-Martínez, J. Phys. Chem. Lett. 2020, 11, 670−677.
https://pubs.acs.org/doi/10.1021/acs.jpclett.9b03574

The irradiation of spherical gold nanoparticles with nanosecond laser pulses induces shape transformations yielding nanocrystals with an inner cavity. The experimental observations suggest the existence of a subtle balance between the heating and cooling processes experienced by the nanocrystals, which induce their expansion and subsequent recrystallization keeping exogenous matter inside.

Ab initio intermolecular potential energy surface for the CO2—N2 system and related thermophysical properties
J.-P. Crusius, R. Hellmann, J. C. Castro-Palacio, and V. Vesovic, J. Chem. Phys. 148, 214306 (2018).
https://aip.scitation.org/doi/full/10.1063/1.5034347

A four-dimensional potential energy surface (PES) for the interaction between a rigid carbon dioxide molecule
and a rigid nitrogen molecule was constructed based on quantum-chemical ab initio calculations up to the coupled-cluster level with single, double, and perturbative triple excitations. The CO2—N2 cross second virial coefficient as well as the dilute gas shear viscosity, thermal conductivity, and binary diffusion coefficient of CO2—N2 mixtures were calculated for temperatures up to 2000 K to validate the PES and to provide reliable reference values
for these important properties.

Rotational relaxation of CF^+ (X^1 Sigma) in collision with He (1^S)
O. Denis-Alpizar, N. Inostroza, and J. C. Castro Palacio, Monthly Notices of the Royal Astronomical Society, 473 (2), 1438-1443 (2018).
https://academic.oup.com/mnras/article/doi/10.1093/mnras/stx2422/4191294/Rotational-relaxation-of-CFX1%CE%A3-in-collision-with

Dilute gas viscosity of n-alkanes represented by rigid Lennard-Jones chains
J. C. Castro-Palacio, R. Hellmann and V. Vesovic, Mol. Phys. 114, 21, (2016) 3171-3182.
http://www.tandfonline.com/doi/full/10.1080/00268976.2016.1222456

Collision-induced rotational excitation in N+2 (2Σ+g, v = 0)–Ar: Comparison of computations and experiment
O. T. Unke, J. C. Castro-Palacio, R. J. Bemish, and M. Meuwly, ”, J. Chem. Phys. 144, 224307 (2016).
http://aip.scitation.org/doi/full/10.1063/1.4951697?showFTTab=true&containerItemId=content%2Faip%2Fjournal%2Fapl&

Reactions involving N and O atoms dominate the energetics of the reactive air flow around spacecraft when reentering the atmosphere in the hypersonic flight regime. A potential energy surface (PES) for the ground state of the NO2 molecule is constructed based on high-level ab initio calculations and represented using the reproducible kernel Hilbert space method and Legendre polynomials. The thermal rate coefficients for reactive processes involving O(3P) and NO(2Π) have been calculated using this PES and Monte Carlo integration.

Extended canonical Monte Carlo methods: Improving accuracy of microcanonical calculations using a re-weighting technique
L. Velazquez and J. C. Castro-Palacio, Phys. Rev. E 91, 033308 (2015).
https://journals.aps.org/pre/abstract/10.1103/PhysRevE.91.033308

Computational study of the O(3P) + NO(2π) reaction at temperatures relevant to the Hypersonic Flight Regime
J. C. Castro-Palacio, T. Nagy, and M. Meuwly, J. Chem. Phys. 141, 164319 (2014).
http://aip.scitation.org/doi/10.1063/1.4897263

Normal and hyperspherical mode analysis of NO doped Kr crystal upon Rydberg excitation of the impurity
J. C. Castro Palacio, L. Velazquez, A. Lombardi, V. Aquilanti, J. Rubayo-Soneira, J. Chem. Phys. 126, 174701 (2007).
http://aip.scitation.org/doi/10.1063/1.2730786

Molecular dynamics simulations and both normal mode and hyperspherical mode analyses of NO-doped Kr solid are carried out in order to get insights into the structural relaxation of the medium upon electronic excitation of the NO molecule. A combined study is reported on the time evolution of the cage radius
and on the density of vibrational states, according to the hyperspherical and normal mode analyses.
For the hyperspherical modes, hyper-radial and grand angular contributions are considered.