@article{13251,
  abstract     = {A rotating organic cation and a dynamically disordered soft inorganic cage are the hallmark features of organic-inorganic lead-halide perovskites. Understanding the interplay between these two subsystems is a challenging problem, but it is this coupling that is widely conjectured to be responsible for the unique behavior of photocarriers in these materials. In this work, we use the fact that the polarizability of the organic cation strongly depends on the ambient electrostatic environment to put the molecule forward as a sensitive probe of the local crystal fields inside the lattice cell. We measure the average polarizability of the C/N–H bond stretching mode by means of infrared spectroscopy, which allows us to deduce the character of the motion of the cation molecule, find the magnitude of the local crystal field, and place an estimate on the strength of the hydrogen bond between the hydrogen and halide atoms. Our results pave the way for understanding electric fields in lead-halide perovskites using infrared bond spectroscopy.},
  author       = {Wei, Yujing and Volosniev, Artem and Lorenc, Dusan and Zhumekenov, Ayan A. and Bakr, Osman M. and Lemeshko, Mikhail and Alpichshev, Zhanybek},
  issn         = {1948-7185},
  journal      = {The Journal of Physical Chemistry Letters},
  keywords     = {General Materials Science, Physical and Theoretical Chemistry},
  number       = {27},
  pages        = {6309--6314},
  publisher    = {American Chemical Society},
  title        = {{Bond polarizability as a probe of local crystal fields in hybrid lead-halide perovskites}},
  doi          = {10.1021/acs.jpclett.3c01158},
  volume       = {14},
  year         = {2023},
}

@article{14261,
  abstract     = {In this work, a generalized, adapted Numerov implementation capable of determining band structures of periodic quantum systems is outlined. Based on the input potential, the presented approach numerically solves the Schrödinger equation in position space at each momentum space point. Thus, in addition to the band structure, the method inherently provides information about the state functions and probability densities in position space at each momentum space point considered. The generalized, adapted Numerov framework provided reliable estimates for a variety of increasingly complex test suites in one, two, and three dimensions. The accuracy of the proposed methodology was benchmarked against results obtained for the analytically solvable Kronig-Penney model. Furthermore, the presented numerical solver was applied to a model potential representing a 2D optical lattice being a challenging application relevant, for example, in the field of quantum computing.},
  author       = {Gamper, Jakob and Kluibenschedl, Florian and Weiss, Alexander K.H. and Hofer, Thomas S.},
  issn         = {1948-7185},
  journal      = {Journal of Physical Chemistry Letters},
  number       = {33},
  pages        = {7395--7403},
  publisher    = {American Chemical Society},
  title        = {{Accessing position space wave functions in band structure calculations of periodic systems - a generalized, adapted numerov implementation for one-, two-, and three-dimensional quantum problems}},
  doi          = {10.1021/acs.jpclett.3c01707},
  volume       = {14},
  year         = {2023},
}

@article{17861,
  abstract     = {Molecular one-dimensional topological insulators (1D TIs), described by the Su-Schrieffer-Heeger (SSH) model, are a new class of molecular electronic wires whose low-energy topological edge states endow them with high electrical conductivity. However, when these 1D TIs become long, the high conductance is not sustained because the coupling between the edge states decreases with increasing length. Here, we present a new design where we connect multiple short 1D SSH TI units linearly or in a cycle to create molecular wires with a continuous topological state density. Using a tight-binding method, we show that the linear system gives a length-independent conductance. The cyclic systems show an interesting odd-even effect, with unit transmission in the topological limit, but zero transmission in the trivial limit. Furthermore, based on our calculations, we predict that these systems can support resonant transmission with a quantum of conductance. We can further expand these results to phenylene-based linear and cyclic 1D TI systems and confirm the length-dependent conductance in such systems. },
  author       = {Li, Liang and Nuckolls, Colin and Venkataraman, Latha},
  issn         = {1948-7185},
  journal      = {The Journal of Physical Chemistry Letters},
  number       = {22},
  pages        = {5141--5147},
  publisher    = {American Chemical Society},
  title        = {{Designing long and highly conducting molecular wires with multiple nontrivial topological states}},
  doi          = {10.1021/acs.jpclett.3c01081},
  volume       = {14},
  year         = {2023},
}

@article{17934,
  abstract     = {We measure the conductance of unmodified peptides at the single-molecule level using the scanning tunneling microscope-based break-junction method, utilizing the N-terminal amine group and the C-terminal carboxyl group as gold metal-binding linkers. Our conductance measurements of oligoglycine and oligoalanine backbones do not rely on peptide side-chain linkers. We compare our results with alkanes terminated asymmetrically with an amine group on one end and a carboxyl group on the other to show that peptide bonds decrease the conductance of an otherwise saturated carbon chain. Using a newly developed first-principles approach, we attribute the decrease in conductance to charge localization at the peptide bond, which reduces the energy of the frontier orbitals relative to the Fermi energy and the electronic coupling to the leads, lowering the tunneling probability. Crucially, this manifests as an increase in conductance decay of peptide backbones with increasing length when compared with alkanes.},
  author       = {Brisendine, Joseph M. and Refaely-Abramson, Sivan and Liu, Zhen-Fei and Cui, Jing and Ng, Fay and Neaton, Jeffrey B. and Koder, Ronald L. and Venkataraman, Latha},
  issn         = {1948-7185},
  journal      = {The Journal of Physical Chemistry Letters},
  number       = {4},
  pages        = {763--767},
  publisher    = {American Chemical Society},
  title        = {{Probing charge transport through peptide bonds}},
  doi          = {10.1021/acs.jpclett.8b00176},
  volume       = {9},
  year         = {2018},
}

@article{9681,
  abstract     = {One of the most prominent consequences of the quantum nature of light atomic nuclei is that their kinetic energy does not follow a Maxwell–Boltzmann distribution. Deep inelastic neutron scattering (DINS) experiments can measure this effect. Thus, the nuclear quantum kinetic energy can be probed directly in both ordered and disordered samples. However, the relation between the quantum kinetic energy and the atomic environment is a very indirect one, and cross-validation with theoretical modeling is therefore urgently needed. Here, we use state of the art path integral molecular dynamics techniques to compute the kinetic energy of hydrogen and oxygen nuclei in liquid, solid, and gas-phase water close to the triple point, comparing three different interatomic potentials and validating our results against equilibrium isotope fractionation measurements. We will then show how accurate simulations can draw a link between extremely precise fractionation experiments and DINS, therefore establishing a reliable benchmark for future measurements and providing key insights to increase further the accuracy of interatomic potentials for water.},
  author       = {Cheng, Bingqing and Behler, Jörg and Ceriotti, Michele},
  issn         = {1948-7185},
  journal      = {The Journal of Physical Chemistry Letters},
  number       = {12},
  pages        = {2210--2215},
  publisher    = {American Chemical Society},
  title        = {{Nuclear quantum effects in water at the triple point: Using theory as a link between experiments}},
  doi          = {10.1021/acs.jpclett.6b00729},
  volume       = {7},
  year         = {2016},
}

@article{17954,
  abstract     = {Guidelines to predict trends in the electrical conductance of molecules have been developed for the π-system of conjugated systems. Little is known, however, about the conductance of the underlying σ-systems because the π-system usually dominates the transport. Here we study a family of bipyridine-based molecules using STM-break junction experiments and density functional theory transport calculations. We use different lengths and substitution patterns to probe the role of both the σ-system and the π-system in controlling conductance. By exploiting the destructive interference feature found in the π-system of the meta-coupled six-membered aromatic rings, we show that the conductance of the σ-system of a meta-coupled molecule can be probed directly and can even exceed that of its para-coupled analog. These results add to the understanding of the conductance through the chemically hidden σ-electrons.},
  author       = {Borges, Anders and Fung, E-Dean and Ng, Fay and Venkataraman, Latha and Solomon, Gemma C.},
  issn         = {1948-7185},
  journal      = {The Journal of Physical Chemistry Letters},
  number       = {23},
  pages        = {4825--4829},
  publisher    = {American Chemical Society},
  title        = {{Probing the conductance of the σ-system of bipyridine using destructive interference}},
  doi          = {10.1021/acs.jpclett.6b02494},
  volume       = {7},
  year         = {2016},
}

@article{18023,
  abstract     = {We measure the conductance of single Au−molecule−Au junctions with a series of air-stable diphenylphosphine-terminated molecules using the scanning tunneling microscope-based break junction technique. Thousands of conductance versus displacement traces collected for each molecule are used to statistically analyze junction conductance and evolution upon elongation. Measured conductances for a series of alkane-based molecules exhibit an exponential decrease with increasing length, as expected for saturated molecules, with a tunneling decay constant of 0.98 ± 0.04. Measurements of junction elongation indicate strong metal−molecule binding, with a length that increases with the number of methylene groups in the backbone. Measured conductance histograms for four molecules with short, unsaturated backbones (e.g., benzene) are much broader with less well-defined peaks. These measurements are supported by density function theory calculations. The phosphine binds selectively to under-coordinated gold atoms through a donor−acceptor bond with a binding energy of about 1 eV. The calculated tunnel coupling correlates very well with experiment.},
  author       = {Parameswaran, R. and Widawsky, J. R. and Vázquez, H. and Park, Y. S. and Boardman, B. M. and Nuckolls, C. and Steigerwald, M. L. and Hybertsen, M. S. and Venkataraman, Latha},
  issn         = {1948-7185},
  journal      = {The Journal of Physical Chemistry Letters},
  number       = {14},
  pages        = {2114--2119},
  publisher    = {American Chemical Society},
  title        = {{Reliable formation of single molecule junctions with air-stable diphenylphosphine linkers}},
  doi          = {10.1021/jz100656s},
  volume       = {1},
  year         = {2010},
}