Ab initio molecular dynamics of liquid water using embedded-fragment second-order many-body perturbation theory towards its accurate property prediction

A direct, simultaneous calculation of properties of a liquid using an ab initio electron-correlated theory has long been unthinkable. Here we present structural, dynamical, and response properties of liquid water calculated by ab initio molecular dynamics using the embedded-fragment spin-component-scaled second-order many-body perturbation method with the aug-cc-pVDZ basis set. This level of theory is chosen as it accurately and inexpensively reproduces the water dimer potential energy surface from the coupled-cluster singles, doubles, and noniterative triples with the augcc-pVQZ basis set, which is nearly exact. The calculated radial distribution function, self-diffusion coefficient, coordinate number, and dipole moment, as well as the infrared and Raman spectra are in excellent agreement with experimental results. The shapes and widths of the OH stretching bands in the infrared and Raman spectra and their isotropic-anisotropic Raman noncoincidence, which reflect the diverse local hydrogen-bond environment, are also reproduced computationally. The simulation also reveals intriguing dynamic features of the environment, which are difficult to probe experimentally, such as a surprisingly large fluctuation in the coordination number and the detailed mechanism by which the hydrogen donating water molecules move across the first and second shells, thereby causing this fluctuationopen

The water dimer II: Theoretical investigations

As the archetype of aqueous hydrogen bonding, the water dimer has been extensively studied by both theory and experiment for nearly seven decades. In this article, we present a detailed chronological review of the theoretical advances made using electronic structure methods to address the structure, hydrogen bonding and vibrational spectroscopy of the water dimer, as well as the role of its potential energy surface in the development of classical force fields to describe intermolecular interactions in clusters and the condensed phases of water

The water dimer II: Theoretical investigations

As the archetype of aqueous hydrogen bonding, the water dimer has been extensively studied by both theory and experiment for nearly seven decades. In this article, we present a detailed chronological review of the theoretical advances made using electronic structure methods to address the structure, hydrogen bonding and vibrational spectroscopy of the water dimer, as well as the role of its potential energy surface in the development of classical force fields to describe intermolecular interactions in clusters and the condensed phases of water

A molecular level study of the aqueous microsolvation of acetylene

We present an analysis of the structural, energetic and spectral features associated with the different hydrogen bonded networks found in the first few acetylene-water clusters AW(n) (n = 1-4) from first principles calculations. Contrary to the predictions of an empirical interaction potential, acetylene is incorporated into a hydrogen bonded ring when it clusters with two or three water molecules. This structural pattern changes for n = 4 with the formation of a water tetramer interacting with acetylene. This structural transition from n = 3 to 4 is spectroscopically manifested by a qualitative change in the appearance of the infrared spectra of the corresponding global minima. (C) 2001 Published by Elsevier Science B.V

Modular Polymer Biosensors by Solvent Immersion Imprint Lithography.

We recently demonstrated Solvent Immersion Imprint Lithography (SIIL), a rapid benchtop microsystem prototyping technique, including polymer functionalization, imprinting and bonding. Here, we focus on the realization of planar polymer sensors using SIIL through simple solvent immersion without imprinting. We describe SIIL's impregnation characteristics, including an inherent mechanism that not only achieves practical doping concentrations, but their unexpected 2-fold enhancement compared to the immersion solution. Subsequently, we developed and characterized optical sensors for detecting molecular O2. To this end, a substantially high dynamic range is reported, including its control through the immersion duration, a manifestation of SIIL's modularity. Overall, SIIL exhibits the potential of improving the operating characteristics of polymer sensors, while significantly accelerating their prototyping, as it requires a few seconds of processing and no need for substrates or dedicated instrumentation. These are critical for O2 sensing as probed by way of example here, as well as any polymer permeable reactant

Modular Polymer Biosensors by Solvent Immersion Imprint Lithography.

We recently demonstrated Solvent Immersion Imprint Lithography (SIIL), a rapid benchtop microsystem prototyping technique, including polymer functionalization, imprinting and bonding. Here, we focus on the realization of planar polymer sensors using SIIL through simple solvent immersion without imprinting. We describe SIIL's impregnation characteristics, including an inherent mechanism that not only achieves practical doping concentrations, but their unexpected 2-fold enhancement compared to the immersion solution. Subsequently, we developed and characterized optical sensors for detecting molecular O2. To this end, a substantially high dynamic range is reported, including its control through the immersion duration, a manifestation of SIIL's modularity. Overall, SIIL exhibits the potential of improving the operating characteristics of polymer sensors, while significantly accelerating their prototyping, as it requires a few seconds of processing and no need for substrates or dedicated instrumentation. These are critical for O2 sensing as probed by way of example here, as well as any polymer permeable reactant