Tunneling Diffusion of Excess Protons in Amorphous Solid Water at 10 and 80 K

Lee, Du‐Hyeong; Kang, Hani; Kang, Heon

doi:10.1021/acs.jpcc.8b11829

Cited by 7 publications

(14 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…MD simulations indicate that the proton-hopping rate in ice I h is significantly reduced as the temperature decreases from 270 to 50 K, and it becomes almost zero in ice I c at 50 K . Lee et al investigated this issue by performing experiments to measure the proton-transfer efficiency from a donor (H 3 O + ) to an acceptor (NH 3 ) embedded in ASW at temperatures of 10–80 K. The proton-transport distance was controlled by changing the separation distance between the donor and the acceptor in the samples. They observed that protons migrated across a distance of approximately 10 water molecules on average.…”

Section: Proton Transport In Icementioning

confidence: 99%

Proton Transport and Related Chemical Processes of Ice

Lee

Kang

2021

J. Phys. Chem. B

Self Cite

View full text Add to dashboard Cite

Excess protons play a key role in the chemical reactions of ice because of their exceptional mobility, even when the diffusion of atoms and molecules is suppressed in ice at low temperatures. This article reviews the current state of knowledge on the properties of excess protons in ice, with a focus on the involvement of protons in chemical reactions. The mechanism of efficient proton transport in ice, which involves a proton-hopping relay along the hydrogen-bond ice network and the reorientation of water, is discussed and compared with the inefficient transport of hydroxide in ice. Distinctly different properties of protons residing in the ice interior and on the ice surface are emphasized. Recent observations of the spontaneous occurrence of reactions in ice at low temperatures, which include the dissociation of protic acids and the hydrolysis of acidic oxides, are discussed with regard to the kinetic and thermodynamic effects of mobile protons on the promotion of unique chemical processes of ice.

show abstract

Section: Proton Transport In Icementioning

confidence: 99%

Proton Transport and Related Chemical Processes of Ice

Lee

Kang

2021

J. Phys. Chem. B

Self Cite

View full text Add to dashboard Cite

show abstract

“…To understand chemical processes in polar environments or interstellar media, unusual chemical reactions on ice-Ih surfaces have been studied with sophisticated experimental techniques [50,[77][78][79][80][81][82]. Theoretical approaches using the ab initio calculations have also been applied to the adsorption of specific adsorbents on ice-Ih surfaces, such as acids (HOCl, HCOOH, and CH 3 COOH), halide ions (F − , Cl − , and Br − ), alkali metals (Na and Na + ), and heavy metals (Hg 0 ) [19,49,83,84].…”

Section: Hg 2+ On Ice-ihmentioning

confidence: 99%

“…In addition, although we prepared surface structures of illite, muscovite, and ice-Ih with different structural defects, more complicated structural defects and disorders than those considered in this study would also exist. For example, ice-Ih has been known to have ionic defects such as hydronium (H 3 O + ) and hydroxide (OH − ) induced from structural disorders as follows [77][78][79][80][81]85]: proton disorder associated with molecular disorientation of H 2 O molecules at a finite temperature (>72 K) within the constraints of the Bernal-Fowler-Pauling ice rules [27][28][29]87], quasi-randomly distributed dangling H and O atoms formed by the full-or half-bilayer terminations [51,82], molecular point defects due to sublimation of H 2 O molecules [53,88,89], proton defects caused by the Grotthuss mechanism [77,78,82], and a quasi-liquid layer arising from thermally induced molecular disorder [50,77,79,82,[90][91][92].…”

Section: Limitation and Future Studymentioning

confidence: 99%

“…The conventional ab initio calculations used in this study provide only the energy of the electronic contribution at 0 K [93]. Because adsorption of Hg compounds on ice surfaces in polar regions occurs at finite temperatures (>200 K), thermally induced structural disorder [50,77,79,82,[90][91][92], hopping of excess protons [77,78,82], and vibrational energy and entropy [9] should be explored in future studies to obtain a comprehensive understanding of the consequent changes in the surface reactivity of ice and the Hg adsorption rate.…”

Section: Limitation and Future Studymentioning

confidence: 99%

See 1 more Smart Citation

Atomistic View of Mercury Cycling in Polar Snowpacks: Probing the Role of Hg2+ Adsorption Using Ab Initio Calculations

Han

Lee

et al. 2019

Minerals

View full text Add to dashboard Cite

Photochemical oxidation of atmospheric elemental mercury (Hg0) promotes reactive oxidized Hg (HgII) adsorption on particles and deposition to the polar snowpack. The deposited Hg either returns to the atmosphere via photochemical reduction or remains in the snowpack depending on the strength of adsorption. In this study, we performed ab initio calculations to understand the atomic-level cause of the fate of adsorbed Hg by determining the adsorption affinity for Hg2+, the simplest form of HgII, of barite, halite, muscovite, illite, and ice-Ih as potential adsorbents. The adsorption affinity was estimated by calculating the energy required to dissociate adsorbed Hg2+ from the adsorbents. The results reveal that Hg2+ is stable on the surfaces of the selected adsorbents, except barite, but is prone to photodissociation under solar ultraviolet radiation. This mild adsorption is expected to contribute to the bidirectional exchange of Hg between the atmosphere and the polar snowpack. Thus, this theoretical approach can provide complementary perspectives on polar Hg dynamics beyond the limitations of field and laboratory experiments. Further studies on more complicated and realistic adsorption models with different HgII species and adsorbent surfaces having diverse defective structures are required to better comprehend air–snow Hg cycling in the polar regions.

show abstract

“…As we will see in the following sections, the form of the Frenkel Hamiltonian allows us to easily map unitary qubit operations onto excitonic circuit geometries. As has been shown in previous studies, 31,32 the details of the molecular structure of the dyes, such as the disorder of the molecular system, can be encoded in the elements of the Hamiltonian. The parameters of the Frenkel Hamiltonian can also be determined from classical molecular dynamics together with semiempirical electronic structure calculations on the electronically excited molecular system.…”

Section: Frenkel Exciton Modelmentioning

confidence: 79%

On the Design of Molecular Excitonic Circuits for Quantum Computing: The Universal Quantum Gates

Castellanos¹,

Dodin²,

Willard

2019

Preprint

View full text Add to dashboard Cite

This manuscript presents a strategy for controlling the transformation of excitonic states through the design of circuits made up of coupled organic dye molecules. Specifically, we show how unitary transformation matrices can be mapped to the Hamiltonians of physical systems of dye molecules with specified geometric and chemical properties.The evolution of these systems over specific times encode the action of the unitary transformation. We identify the bounds on complexity of the transformations that can be represented by these circuits. We formalize this strategy and apply it to identify the excitonic circuits of the four universal quantum logic gates: NOT, Hadamard, π/8 and CNOT. We discuss the properties of these circuits and how their performance is expected to be influenced by the presence of environmental noise. We quantify the bounds on the spectroscopic properties of organic dye circuits under which single-qubit unitary transformations are possible.The elementary component of a quantum computer -a qubit -is a two-state quantum system. A qubit can be constructed from many different physical systems, including a pair of coupled organic dye molecules sharing a single electronic excitation (i.e., an exciton).Using this kind of qubit it is therefore possible, at least in principle, to develop quantum computing platforms that operate via the excited state dynamics of specifically designed excitonic circuits comprised of multiple dye molecules in precise geometric arrangements. In this manuscript, we introduce a general strategy for designing excitonic circuits for quantum computation. We apply this strategy to identify fundamental bounds on the computational complexity that these circuits can support and identify the physical requirements for performing universal quantum logic gate operations on one-and two-qubit systems. This study therefore sets the groundwork for enabling the development of programmable dye-based quantum computing platforms.Excitonic circuits are constructed by arranging the positions and orientations of dye molecules. The evolution of excitons within the circuit is determined by the intermolecular electronic coupling network and the electronic properties of the dyes. The electronic coupling between dye molecules is programmed by their intermolecular spacing and orientation. 1 Supermolecular support structures, such as proteins, 2,3 metal-organic frameworks, 4 and DNA nanostructures, 5,6 can be used to situate dye molecules with coupling networks that are designed to control certain aspects of exciton dynamics. The resulting dynamical control can be used to implement the state transformations required for quantum computation.Quantum computing offers several key advantages over traditional classical computing and is poised to make a transformative impact on certain areas of the information sciences, such as cryptography and molecular simulation. 7,8 However, despite enormous potential for broad technological impact, quantum computing presents unique implementation challenges that have thus f...

show abstract

Tunneling Diffusion of Excess Protons in Amorphous Solid Water at 10 and 80 K

Cited by 7 publications

References 54 publications

Proton Transport and Related Chemical Processes of Ice

Proton Transport and Related Chemical Processes of Ice

Atomistic View of Mercury Cycling in Polar Snowpacks: Probing the Role of Hg2+ Adsorption Using Ab Initio Calculations

On the Design of Molecular Excitonic Circuits for Quantum Computing: The Universal Quantum Gates

Contact Info

Product

Resources

About