Ab-initio Study of NMR Chemical Shifts of Water Under Normal and Supercritical Conditions

Sebastiani, Daniel; Parrinello, Michele

doi:10.1002/1439-7641(20020816)3:8<675::aid-cphc675>3.0.co;2-o

Cited by 71 publications

(65 citation statements)

References 17 publications

(31 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Pioneering density functional theory simulations (29,30) have obtained qualitative agreement with these experiments. Unfortunately, however, the NMR chemical shift computed by density functional perturbation theory does not yet allow one to achieve the same exquisite level of accuracy that is characteristic of NMR experiments: Details of the calculation, such as the exchange-correlation functional, pseudopotential, and system size, can change the results by more than 1 ppm (31).…”

Section: Significancementioning

confidence: 57%

Nuclear quantum effects and hydrogen bond fluctuations in water

Ceriotti

Cuny

Parrinello

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

219

260

View full text Add to dashboard Cite

The hydrogen bond (HB) is central to our understanding of the properties of water. However, despite intense theoretical and experimental study, it continues to hold some surprises. Here, we show from an analysis of ab initio simulations that take proper account of nuclear quantum effects that the hydrogen-bonded protons in liquid water experience significant excursions in the direction of the acceptor oxygen atoms. This generates a small but nonnegligible fraction of transient autoprotolysis events that are not seen in simulations with classical nuclei. These events are associated with major rearrangements of the electronic density, as revealed by an analysis of the computed Wannier centers and 1 H chemical shifts. We also show that the quantum fluctuations exhibit significant correlations across neighboring HBs, consistent with an ephemeral shuttling of protons along water wires. We end by suggesting possible implications for our understanding of how perturbations (solvated ions, interfaces, and confinement) might affect the HB network in water.path integral molecular dynamics | generalized Langevin equation thermostat | ab initio liquid water D espite its apparent simplicity, liquid water exhibits a number of anomalous properties, such as a decrease in density on freezing, an isobaric density maximum, and its unusually high dielectric constant and heat capacity (1). These, together with its unquestionable importance for climate and life on Earth, have made this substance a subject of intense research by both experiments and simulations.The central concept that has been used to rationalize the peculiar behavior of water is that of the hydrogen bond (HB) (2). The nature of this bond in water has been studied in depth by atomistic computer simulations, which have investigated how it is affected by ionic and electronic polarizability (3, 4), pressure and temperature (5, 6), and nuclear quantum effects (NQEs) (7-9). Furthermore, ab initio molecular dynamics (MD) simulations have been used to shed light on autoionization (10, 11), a process with profound implications for the chemistry of aqueous solutions.In this paper, we investigate the impact of NQEs on the HB in pure water, finding a qualitative increase in fluctuations that leads to a partial dissociation of the covalent O-H bond. The weakening of this covalent bond in the presence of hydrogen bonding is consistent with the red shift of the stretching mode of water upon condensation, as well as with recent experiments demonstrating that selectively exciting the O-H stretch in water leads to a pronounced delocalization of the proton toward the acceptor oxygen atom (12). However, the role of NQEs in governing the extent of this delocalization has not been investigated before now.Our analysis is based on MD simulations of water at different thermodynamic state points, with an ab initio description of the interactions among the nuclei. We also account fully for the quantum nature of the nuclear motion, using a recently developed combination of imaginary time path i...

show abstract

Section: Significancementioning

confidence: 57%

Nuclear quantum effects and hydrogen bond fluctuations in water

Ceriotti

Cuny

Parrinello

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

219

260

View full text Add to dashboard Cite

show abstract

“…The approach developed by Sebastiani and Parrinello, 66 which was shown to give good estimation of NMR shifts, 67 was used. Similar to the procedures adopted by Banyai et al, 68 30 structures were extracted from a NPT MD trajectory of a system of 32 water molecules and the nuclear magnetic shieldings were calculated with the BLYP method 69,70 and the Goedecker type pseudopotentials 71 for the two hydrogen atoms in all water molecules, using the NMR module implemented in the CPMD program.…”

Section: Computational Detailsmentioning

confidence: 99%

Six-site polarizable model of water based on the classical Drude oscillator

Lopes

Roux

et al. 2013

The Journal of Chemical Physics

111

152

View full text Add to dashboard Cite

A polarizable water model, SWM6, was developed and optimized for liquid phase simulations under ambient conditions. Building upon the previously developed SWM4-NDP model, additional sites representing oxygen lone-pairs were introduced. The geometry of the sites is assumed to be rigid. Considering the large number of adjustable parameters, simulated annealing together with polynomial fitting was used to facilitate model optimization. The new water model was shown to yield the correct self-diffusion coefficient after taking the system size effect into account, and the dimer geometry is better reproduced than in the SWM4 models. Moreover, the experimental oxygen-oxygen radial distribution is better reproduced, indicating that the new model more accurately describes the local hydrogen bonding structure of bulk phase water. This was further validated by its ability to reproduce the experimental nuclear magnetic shielding and related chemical shift of the water hydrogen in the bulk phase, a property sensitive to the local hydrogen bonding structure. In addition, comparison of the liquid properties of the SWM6 model is made with those of a number of widely used additive and polarizable models. Overall, improved balance between the description of monomer, dimer, clustered, and bulk phase water is obtained with the new model compared to its SWM4-NDP polarizable predecessor, though application of the model requires an approximately twofold increase on computational resources.

show abstract

“…com. ] visualize ring currents in the presence of an external magnetic field [46] or the integration of fluid dynamics specific visualization techniques inside an atomistic visualization. [47] Graphic cards already provide enhanced rendering, like advanced surface textures or ambient occlusion to simulate realistic lighting.…”

Section: Expanding Representationsmentioning

confidence: 99%

Visualization: A cognition amplifier

Valle

2013

Int. J. Quantum Chem.

View full text Add to dashboard Cite

Computational codes produce huge quantities of numbers, but what scientists seek is insight. That is, they want to know what these numbers reveal about the phenomena under study. Visualization, transforming data into graphical structures, can enhance research effectiveness by leveraging human visual perceptual capabilities. Evolved over millions of years for survival, these capabilities enable us to see structures and perceive correlations and regularities around us. When properly visualized, we can apply these same perception capabilities, with little rational effort, to our data. In this tutorial, after analyzing a short definition of visualization, its major concepts will be seen in action using a popular chemistry visualization tool. The tutorial closes discussing paths for continued exploration of the future potential of these visualization techniques and tools. V C 2013 Wiley Periodicals, Inc.

show abstract

Ab-initio Study of NMR Chemical Shifts of Water Under Normal and Supercritical Conditions

Cited by 71 publications

References 17 publications

Nuclear quantum effects and hydrogen bond fluctuations in water

Nuclear quantum effects and hydrogen bond fluctuations in water

Six-site polarizable model of water based on the classical Drude oscillator

Visualization: A cognition amplifier

Contact Info

Product

Resources

About