Carbon Dioxide, Bicarbonate and Carbonate Ions in Aqueous Solutions at Deep Earth Conditions

In the course of our investigations of the adsorption of ions to the air-water interface, we previously reported the surprising result that doubly-charged carbonate anions exhibit a stronger surface affinity than do singly-charged bicarbonate anions. In contrast to monovalent, weakly hydrated anions, which generally show enhanced concentrations in the interfacial region, multivalent (and strongly hydrated) anions are expected to show much weaker surface propensity. In the pre...

Quantum molecular dynamic simulations are introduced to study the dynamical, electrical, and optical properties of carbon dioxide under dynamic compressions. The principal Hugoniot derived from the calculated equation of states is demonstrated to be well accordant with experimental results. Molecular dissociation and recombination are investigated through pair correlation functions, and decomposition of carbon dioxide is found to be between 40 and 50 GPa along the Hugoniot, w...

Subsurface fluid flow and solute transport are pivotal in addressing pressing energy, environmental, and societal challenges, such as geological CO2 storage. Basaltic rocks have gained prominence as suitable geological substrates for injecting substantial CO2 volumes and carbon mineralization, driven by their widespread occurrence, high concentrations of cation-rich silicate minerals, reported fast mineralization rate, and favorable characteristics such as porosity, permeabil...

The dissolution of CO$_2$ in water followed by the subsequent hydrolysis reactions is of great importance to the global carbon cycle and carbon capture and storage. Despite enormous previous studies, the reaction pathways and kinetics are still not fully understood at the atomistic scale. Here, we constructed Markov state models based on $ab\ initio$ molecular dynamics simulations to elucidate the reaction mechanisms and kinetics of dissolved carbon in supercritical water bot...

In this work, the effect of the range of the dispersive interactions in the determination of the three-phase coexistence line of the CO$_2$ and CH$_4$ hydrates has been studied. In particular, the temperature ($T_3$) at which solid hydrate, water, and liquid CO$_2$/gas CH$_4$ coexist has been determined through molecular dynamics simulations using different cut-off values (from 0.9 to 1.6 nm) for the dispersive interactions. The $T_3$ of both hydrates has been determined usin...

The solvation of carbon monoxide (CO) in liquid water is important for understanding its toxicological effects and biochemical roles. In this paper, we use ab initio molecular dynamics (AIMD) and CCSD(T)-F12 calculations to assess the accuracy of the Straub and Karplus molecular mechanical (MM) model for CO(aq). The CCSD(T)-F12 CO--H2O potential energy surfaces show that the most stable structure corresponds to water donating a hydrogen bond to the C center. The MM-calculated...

We study conditions under which carbon clusters of different sizes form and stabilize. {We describe an approach to equilibrium by simulating tenuous carbon gas dynamics to long times.} First, we use reactive molecular dynamics simulations to describe the nucleation of long chains, large clusters, and complex cage structures in carbon and hydrogen rich interstellar gas phases. We study how temperature, particle density, presence of hydrogen, and carbon inflow affect the nuclea...

Carbon dioxide (CO$_2$) sequestration in saline aquifers has been introduced as one of the most practical, long-term, and safe solutions to tackle a growing threat originating from the emission of CO$_2$. Successfully executing and planning the process necessitates a comprehensive understanding of CO$_2$ transport properties -- particularly the diffusion coefficient, influencing the behavior of CO$_2$ dissolution in water/brine regarding the shape of viscous fingers, the onse...

Accurately modeling dense plasmas over wide ranging conditions of pressure and temperature is a grand challenge critically important to our understanding of stellar and planetary physics as well as inertial confinement fusion. In this work, we employ Kohn-Sham density functional theory (DFT) molecular dynamics (MD) to compute the properties of carbon at warm and hot dense matter conditions in the vicinity of the principal Hugoniot. In particular, we calculate the equation of ...

Biphasic interfaces are complex but fascinating regimes that display a number of properties distinct from those of the bulk. The CO$_2$-H$_2$O interface, in particular, has been the subject of a number of studies on account of its importance for the carbon life cycle as well as carbon capture and sequestration schemes. Despite this attention, there remain a number of open questions on the nature of the CO$_2$-H$_2$O interface, particularly concerning the interfacial tension a...