Unveiling the Janus-Like Properties of OH(-).

Using ab initio simulations, we explore the glassy landscape of the OH(-)(H2O)20 cluster and its infrared spectrum. We show that the OH(-) has an amphiphilic Janus-type behavior like the hydronium ion induced by the ability of its O-H bond to be buried inside of the cluster or exposed at the surface with different coordination numbers. Recent infrared experiments of aqueous NaOH have found two pronounced peaks at 2000 and 2850 cm(-1) [Mandal, A.; J. Chem. Phys. 2014, 140, 1-12]. The microscopic origins of these spectral features remain elusive. Herein, we disentangle the contribution of the spectra between 1700 and 3000 cm(-1) in terms of the microscopic solvation structure of OH(-) and dub this as the amphiphilic band. The delocalized nature of OH(-) results in a red shift to the O-H stretch, which mixes with bend-vibrations, the extent to which is tuned by the local coordination number. These results have important bearing on understanding the spectroscopic signatures of OH(-) in environments like the air-water interface.

[1]  Kari Laasonen,et al.  Ab initio molecular dynamics simulation of the solvation and transport of H3O+ and OH- ions in water , 1995 .

[2]  Ali Hassanali,et al.  Proton transfer through the water gossamer , 2013, Proceedings of the National Academy of Sciences.

[3]  A. Laio,et al.  Metadynamics: a method to simulate rare events and reconstruct the free energy in biophysics, chemistry and material science , 2008 .

[4]  M. Eigen,et al.  Self-dissociation and protonic charge transport in water and , 1958, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[5]  Yanli Wang,et al.  Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials , 2009 .

[6]  Michele Parrinello,et al.  Quickstep: Fast and accurate density functional calculations using a mixed Gaussian and plane waves approach , 2005, Comput. Phys. Commun..

[7]  C. Dellago,et al.  Autoionization in Liquid Water , 2001, Science.

[8]  A. Tokmakoff,et al.  Collective vibrations of water-solvated hydroxide ions investigated with broadband 2DIR spectroscopy. , 2014, The Journal of chemical physics.

[9]  Robert Vácha,et al.  Water surface is acidic , 2007, Proceedings of the National Academy of Sciences.

[10]  G. Voth,et al.  Unusual "amphiphilic" association of hydrated protons in strong acid solution. , 2008, Journal of the American Chemical Society.

[11]  I-Feng W. Kuo,et al.  Hydroxide anion at the air–water interface , 2009 .

[12]  R. Saykally,et al.  Evidence for an enhanced hydronium concentration at the liquid water surface. , 2005, The journal of physical chemistry. B.

[13]  R. Saykally,et al.  Is the liquid water surface basic or acidic? Macroscopic vs. molecular-scale investigations , 2008 .

[14]  I. Hertel,et al.  Interaction between liquid water and hydroxide revealed by core-hole de-excitation , 2008, Nature.

[15]  M. Parrinello,et al.  Canonical sampling through velocity rescaling. , 2007, The Journal of chemical physics.

[16]  Marco Mazzotti,et al.  Controlling and predicting crystal shapes: the case of urea. , 2013, Angewandte Chemie.

[17]  J. Steitz,et al.  A general two-metal-ion mechanism for catalytic RNA. , 1993, Proceedings of the National Academy of Sciences of the United States of America.

[18]  Mark S Gordon,et al.  Nonlinear response time-dependent density functional theory combined with the effective fragment potential method. , 2014, The Journal of chemical physics.

[19]  Ali Hassanali,et al.  The role of the umbrella inversion mode in proton diffusion , 2014 .

[20]  Kai Giese,et al.  ジクロロトロポロンにおける動的水素原子トンネリング 量子的,半古典的及び古典的研究を組み合せた研究 , 2005 .

[21]  J. Kress,et al.  Hydration and mobility of HO-(aq). , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[22]  Teter,et al.  Separable dual-space Gaussian pseudopotentials. , 1996, Physical review. B, Condensed matter.

[23]  D. Chadi,et al.  Special points for Brillouin-zone integrations , 1977 .

[24]  Mark A. Johnson,et al.  Spectroscopic Determination of the OH− Solvation Shell in the OH−·(H2O)n Clusters , 2003, Science.

[25]  Stefano de Gironcoli,et al.  Phonons and related crystal properties from density-functional perturbation theory , 2000, cond-mat/0012092.

[26]  S. Goedecker,et al.  Relativistic separable dual-space Gaussian pseudopotentials from H to Rn , 1998, cond-mat/9803286.

[27]  A. Laio,et al.  Escaping free-energy minima , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[28]  Masayoshi Takahashi,et al.  Zeta potential of microbubbles in aqueous solutions: electrical properties of the gas-water interface. , 2005, The journal of physical chemistry. B.

[29]  L. Halonen,et al.  Global minima of protonated water clusters (H2O)20H+ revisited. , 2012, The journal of physical chemistry. A.

[30]  David J. Wales,et al.  Global minima of protonated water clusters , 2000 .

[31]  A. Soper,et al.  Solvation of hydroxyl ions in water , 2003 .

[32]  A. Chandra,et al.  Hydration structure and dynamics of a hydroxide ion in water clusters of varying size and temperature: Quantum chemical and ab initio molecular dynamics studies , 2012 .

[33]  Parr,et al.  Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. , 1988, Physical review. B, Condensed matter.

[34]  S. Grimme,et al.  A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu. , 2010, The Journal of chemical physics.

[35]  Amalendu Chandra,et al.  Aqueous basic solutions: hydroxide solvation, structural diffusion, and comparison to the hydrated proton. , 2010, Chemical reviews.

[36]  Gregory A Voth,et al.  An improved multistate empirical valence bond model for aqueous proton solvation and transport. , 2008, The journal of physical chemistry. B.

[37]  M. Parrinello,et al.  Aqueous solutions: state of the art in ab initio molecular dynamics , 2014, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[38]  Barbara Kirchner,et al.  TRAVIS - a free analyzer and visualizer for Monte Carlo and molecular dynamics trajectories , 2011, Journal of Cheminformatics.

[39]  Barbara Kirchner,et al.  TRAVIS - a free analyzer and visualizer for Monte Carlo and molecular dynamics trajectories , 2011, Journal of Cheminformatics.

[40]  D. Tobias,et al.  Toward a unified picture of the water self-ions at the air-water interface: a density functional theory perspective. , 2014, The journal of physical chemistry. B.

[41]  J. Beattie,et al.  The surface of neat water is basic. , 2009, Faraday discussions.

[42]  M. Faubel,et al.  Behavior of hydroxide at the water/vapor interface , 2009 .

[43]  Ali Hassanali,et al.  On the recombination of hydronium and hydroxide ions in water , 2011, Proceedings of the National Academy of Sciences.

[44]  Kari Laasonen,et al.  Ab initio molecular dynamics simulation of the solvation and transport of hydronium and hydroxyl ions in water , 1995 .

[45]  Barbara Kirchner,et al.  Computing vibrational spectra from ab initio molecular dynamics. , 2013, Physical chemistry chemical physics : PCCP.

[46]  Per Linse,et al.  Monte Carlo simulations of oppositely charged macroions in solution. , 2005, The Journal of chemical physics.

[47]  Jer-Lai Kuo,et al.  Structure of protonated water clusters: low-energy structures and finite temperature behavior. , 2005, The Journal of chemical physics.

[48]  Matt K. Petersen,et al.  The properties of ion-water clusters. I. The protonated 21-water cluster. , 2005, The Journal of chemical physics.

[49]  Alessandro Laio,et al.  Dissociation mechanism of acetic acid in water. , 2006, Journal of the American Chemical Society.

[50]  G. Richmond,et al.  Spectroscopic studies of solvated hydrogen and hydroxide ions at aqueous surfaces. , 2006, Journal of the American Chemical Society.