References of "Journal of Physical Chemistry Letters"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailModeling Nonreactive Molecule−Surface Systems on Experimentally Relevant Time and Length Scales: Dynamics and Conductance of Polyfluorene on Au(111)
Li, Zhi; Tkatchenko, Alexandre UL; Franco, Ignacio

in Journal of Physical Chemistry Letters (2018), 9

We propose a computationally efficient strategy to accurately model nonreactive molecule−surface interactions that adapts density functional theory calculations with the Tkatchenko−Scheffler scheme for ... [more ▼]

We propose a computationally efficient strategy to accurately model nonreactive molecule−surface interactions that adapts density functional theory calculations with the Tkatchenko−Scheffler scheme for van der Waals interactions into a simple classical force field. The resulting force field requires just two adjustable parameters per atom type that are needed to capture short-range and polarization interactions. The developed strategy allows for classical molecular dynamics simulation of molecules on surfaces with the accuracy of highlevel electronic structure methods but for system sizes (103 to 107 atoms) and timescales (picoseconds to microseconds) that go well beyond what can be achieved with first-principles methods. Parameters for H, sp2 C, and O on Au(111) are developed and employed to atomistically model experiments that measure the conductance of a single polyfluorene on Au(111) as a continuous function of its length. The simulations qualitatively capture both the gross and fine features of the observed conductance decay during initial junction elongation and lead to a revised atomistic understanding of the experiment. [less ▲]

Detailed reference viewed: 98 (0 UL)
Full Text
Peer Reviewed
See detailStructure and Stability of Molecular Crystals with Many-Body Dispersion-Inclusive Density Functional Tight Binding
Mortazavi, Majid; Brandenburg, Jan Gerit; Maurer, Reinhard J. et al

in Journal of Physical Chemistry Letters (2018), 9

Accurate prediction of structure and stability of molecular crystals is crucial in materials science and requires reliable modeling of long-range dispersion interactions. Semiempirical electronic ... [more ▼]

Accurate prediction of structure and stability of molecular crystals is crucial in materials science and requires reliable modeling of long-range dispersion interactions. Semiempirical electronic structure methods are computationally more efficient than their ab initio counterparts, allowing structure sampling with significant speedups. We combine the Tkatchenko−Scheffler van der Waals method (TS) and the many-body dispersion method (MBD) with third-order density functional tight-binding (DFTB3) via a charge population-based method. We find an overall good performance for the X23 benchmark database of molecular crystals, despite an underestimation of crystal volume that can be traced to the DFTB parametrization. We achieve accurate lattice energy predictions with DFT+MBD energetics on top of vdW-inclusive DFTB3 structures, resulting in a speedup of up to 3000 times compared with a full DFT treatment. This suggests that vdW-inclusive DFTB3 can serve as a viable structural prescreening tool in crystal structure prediction. [less ▲]

Detailed reference viewed: 165 (4 UL)
Full Text
Peer Reviewed
See detailMachine learning predictions of molecular properties: Accurate many-body potentials and nonlocality in chemical space
Hansen, K.; Biegler, F.; Ramakrishnan, R. et al

in Journal of Physical Chemistry Letters (2015), 6(12), 2326-2331

Simultaneously accurate and efficient prediction of molecular properties throughout chemical compound space is a critical ingredient toward rational compound design in chemical and pharmaceutical ... [more ▼]

Simultaneously accurate and efficient prediction of molecular properties throughout chemical compound space is a critical ingredient toward rational compound design in chemical and pharmaceutical industries. Aiming toward this goal, we develop and apply a systematic hierarchy of efficient empirical methods to estimate atomization and total energies of molecules. These methods range from a simple sum over atoms, to addition of bond energies, to pairwise interatomic force fields, reaching to the more sophisticated machine learning approaches that are capable of describing collective interactions between many atoms or bonds. In the case of equilibrium molecular geometries, even simple pairwise force fields demonstrate prediction accuracy comparable to benchmark energies calculated using density functional theory with hybrid exchange-correlation functionals; however, accounting for the collective many-body interactions proves to be essential for approaching the "holy grail" of chemical accuracy of 1 kcal/mol for both equilibrium and out-of-equilibrium geometries. This remarkable accuracy is achieved by a vectorized representation of molecules (so-called Bag of Bonds model) that exhibits strong nonlocality in chemical space. In addition, the same representation allows us to predict accurate electronic properties of molecules, such as their polarizability and molecular frontier orbital energies. © 2015 American Chemical Society. [less ▲]

Detailed reference viewed: 159 (3 UL)
Full Text
Peer Reviewed
See detailHard numbers for large molecules: Toward exact energetics for supramolecular systems
Ambrosetti, A.; Alfè, D.; Distasio, R. A. et al

in Journal of Physical Chemistry Letters (2014), 5(5), 849-855

Noncovalent interactions are ubiquitous in molecular and condensed-phase environments, and hence a reliable theoretical description of these fundamental interactions could pave the way toward a more ... [more ▼]

Noncovalent interactions are ubiquitous in molecular and condensed-phase environments, and hence a reliable theoretical description of these fundamental interactions could pave the way toward a more complete understanding of the microscopic underpinnings for a diverse set of systems in chemistry and biology. In this work, we demonstrate that recent algorithmic advances coupled to the availability of large-scale computational resources make the stochastic quantum Monte Carlo approach to solving the Schrödinger equation an optimal contender for attaining "chemical accuracy" (1 kcal/mol) in the binding energies of supramolecular complexes of chemical relevance. To illustrate this point, we considered a select set of seven host-guest complexes, representing the spectrum of noncovalent interactions, including dispersion or van der Waals forces, π-π stacking, hydrogen bonding, hydrophobic interactions, and electrostatic (ion-dipole) attraction. A detailed analysis of the interaction energies reveals that a complete theoretical description necessitates treatment of terms well beyond the standard London and Axilrod-Teller contributions to the van der Waals dispersion energy. © 2014 American Chemical Society. [less ▲]

Detailed reference viewed: 84 (2 UL)
Full Text
Peer Reviewed
See detailSize effects in the interface level alignment of dye-sensitized TiO 2 clusters
Marom, N.; Körzdörfer, T.; Ren, X. et al

in Journal of Physical Chemistry Letters (2014), 5(14), 2395-2401

The efficiency of dye-sensitized solar cells (DSCs) depends critically on the electronic structure of the interfaces in the active region. We employ recently developed dispersion-inclusive density ... [more ▼]

The efficiency of dye-sensitized solar cells (DSCs) depends critically on the electronic structure of the interfaces in the active region. We employ recently developed dispersion-inclusive density functional theory (DFT) and GW methods to study the electronic structure of TiO2 clusters sensitized with catechol molecules. We show that the energy level alignment at the dye-TiO2 interface is the result of an intricate interplay of quantum size effects and dynamic screening effects and that it may be manipulated by nanostructuring and functionalizing the TiO2. We demonstrate that the energy difference between the catechol LUMO and the TiO2 LUMO, which is associated with the injection loss in DSCs, may be reduced significantly by reducing the dimensions of nanostructured TiO2 and by functionalizing the TiO2 with wide-gap moieties, which contribute additional screening but do not interact strongly with the frontier orbitals of the TiO2 and the dye. Precise control of the electronic structure may be achieved via "interface engineering" in functional nanostructures. © 2014 American Chemical Society. [less ▲]

Detailed reference viewed: 77 (3 UL)
Full Text
Peer Reviewed
See detailSeamless and Accurate Modeling of Organic Molecular Materials
Reilly, Anthony M.; Tkatchenko, Alexandre UL

in Journal of Physical Chemistry Letters (2013), 4(6), 1028-1033

The near endless possibilities for assembling molecular materials has long posed a difficult challenge for theory. All crystal-structure prediction methods acknowledge the crucial contribution of van der ... [more ▼]

The near endless possibilities for assembling molecular materials has long posed a difficult challenge for theory. All crystal-structure prediction methods acknowledge the crucial contribution of van der Waals or dispersion interactions, but few go beyond a pairwise additive description of dispersion, ignoring its many-body nature. Here we use two databases to show how a many-body approach to dispersion can seamlessly model both solid and gas-phase interactions within the coveted ``chemical accuracy'' benchmark, while the underlying pairwise approach fails for solid-state interactions due to the absence of many-body polarization and energy contributions. Our results show that recently developed methods that treat the truly collective nature of dispersion interactions are able to reach the accuracy required for predicting molecular materials, when coupled with nonempirical density functionals. [less ▲]

Detailed reference viewed: 77 (3 UL)
Full Text
Peer Reviewed
See detailToward Low-Temperature Dehydrogenation Catalysis: Isophorone Adsorbed on Pd(111)
Liu, Wei; Savara, Aditya; Ren, Xinguo et al

in Journal of Physical Chemistry Letters (2012), 3(5), 582-586

Adsorbate geometry and reaction dynamics play essential roles in catalytic processes at surfaces. Here we present a theoretical and experimental study for a model functional organic/metal interface ... [more ▼]

Adsorbate geometry and reaction dynamics play essential roles in catalytic processes at surfaces. Here we present a theoretical and experimental study for a model functional organic/metal interface: isophorone (C9H14O) adsorbed on the Pd(111) surface. Density functional theory calculations with the Perdew-Burke-Ernzerhoff (PBE) functional including van der Waals (vdW) interactions, in combination with infrared spectroscopy and temperature-programmed desorption (TPD) experiments reveal the reaction pathway between the weakly chemisorbed reactant (C9H14O) and the strongly chemisorbed product (C9H10O), which occurs by the cleavage of four C-H bonds below 250 K. Analysis of the TPD spectrum is consistent with the relatively small magnitude of the activation barrier derived from PBE+vdW calculations, demonstrating the feasibility of low-temperature dehydrogenation. [less ▲]

Detailed reference viewed: 79 (3 UL)