<i>Ab Initio</i>Calculation of Optical Spectra of Liquids: Many-Body Effects in the Electronic Excitations of Water

Garbuio, V.; Cascella, M.; Reining, Lucia; Sole, R. Del; Pulci, Olivia

doi:10.1103/physrevlett.97.137402

Cited by 81 publications

(91 citation statements)

References 31 publications

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“…33 (As discussed below, in our calculations the difference between the band gap of the Cl − solution and of pure water is at most 0.3 eV.) Although a substantial improvement on the PBE result, the PBE0 gap underestimates the value of the quasi particle gap obtained by photoemission experiments (8.7 ± 0.5 eV 46 ), and by GW calculations (8.1 ± 0.2 eV 47 and 8.7 eV 48,49 ). We note that within statistical errors, we obtained the same value of the gap (6.58 ± 0.21 eV) in PBE0/PBE calculations.…”

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confidence: 85%

Communication: Electronic structure of the solvated chloride anion from first principles molecular dynamics

Zhang

Pham

Gygi

et al. 2013

The Journal of Chemical Physics

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We present first principles molecular dynamics simulations of the chloride anion in liquid water performed using gradient-corrected and hybrid density functionals. We show that it is necessary to use hybrid functionals both for the generation of molecular dynamics trajectories and for the calculation of electronic states in order to obtain a qualitatively correct description of the electronic properties of the solution. In particular, it is only with hybrid functionals that the highest occupied molecular orbital of the anion is found above the valence band maximum of water, consistent with photoelectron detachment measurements. Similar results were obtained using many body perturbation theory within the G0W0 approximation.

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confidence: 85%

Communication: Electronic structure of the solvated chloride anion from first principles molecular dynamics

Zhang

Pham

Gygi

et al. 2013

The Journal of Chemical Physics

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“…The GW-BSE approach 9,10 has been successfully applied to a number of different systems ranging from bulk semiconductors, 9 insulators and their surfaces, 11 two-dimensional systems such as graphene 12 and boron nitride layers, 13 metal-molecule interfaces, 6 isolated molecules, [14][15][16] and liquid water. 17 Nevertheless, applications of the approach to larger systems are limited by the extremely demanding computational requirements of both the GW and BSE calculations.…”

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confidence: 99%

Optical properties of bulk semiconductors and graphene/boron nitride: The Bethe-Salpeter equation with derivative discontinuity-corrected density functional energies

2012

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We present an efficient implementation of the Bethe-Salpeter equation (BSE) for optical properties of materials in the projector augmented wave method GPAW. Single-particle energies and wave functions are obtained from the GLLBSC functional which explicitly includes the derivative discontinuity, is computationally inexpensive, and yields excellent fundamental gaps. Electron-hole interactions are included through the BSE using the statically screened interaction evaluated in the random phase approximation. For a representative set of semiconductors and insulators we find excellent agreement with experiments for the dielectric functions, onset of absorption, and lowest excitonic features. For the two-dimensional systems of graphene and hexagonal boron-nitride (h-BN) we find good agreement with previous many-body calculations. For the graphene/h-BN interface, we find that the fundamental and optical gaps of the h-BN layer are reduced by 2.0 eV and 0.7 eV, respectively, compared to freestanding h-BN. This reduction is due to image charge screening which shows up in the GLLBSC calculation as a reduction (vanishing) of the derivative discontinuity.

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“…This behavior is caused by the presence of a non-bonded fraction within the first molecular coordination shell, an effect not directly associated to broken H-bonds, even though the short-range order (SRO) of the liquid reflects the partial collapse of the H-bond network. We argue that the same effect, in absence of H-bond breaking, should explain the post-edge feature of HDA ice.Our approach can be viewed as an approximate version of the Bethe-Salpeter equation (BSE) for electron-hole excitations [15], which was recently applied with success to compute the optical absorption spectra of Ih ice [16] and liquid water [17]. In the present case, we neglect the dynamics of the oxygen 1s core hole, which is localized and long lived on the time scale of the absorption process.…”

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confidence: 99%

“…Our approach can be viewed as an approximate version of the Bethe-Salpeter equation (BSE) for electron-hole excitations [15], which was recently applied with success to compute the optical absorption spectra of Ih ice [16] and liquid water [17]. In the present case, we neglect the dynamics of the oxygen 1s core hole, which is localized and long lived on the time scale of the absorption process.…”

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confidence: 99%

X-Ray Absorption Signatures of the Molecular Environment in Water and Ice

2010

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The x-ray absorption spectra of water and ice are calculated with a many-body approach for electron-hole excitations. The experimental features, including the small effects of temperature change in the liquid, are quantitatively reproduced from molecular configurations generated by abinitio molecular dynamics. The spectral difference between the solid and the liquid is due to two major short range order effects. One, due to breaking of hydrogen bonds, enhances the pre-edge intensity in the liquid. The other, due to a non-bonded molecular fraction in the first coordination shell, affects the main spectral edge in the conversion of ice to water. This effect may not involve hydrogen bond breaking as shown by experiment in high-density amorphous ice.PACS numbers: 36.20. Ng, 71.15.Pd, 32.10.Dk, 78.20.Ci The nature of the hydrogen bond (H-bond) network in water continues to be at the center of scientific debate [1]. A few years ago high-resolution x-ray absorption spectra (XAS) probed the local order of liquid and crystalline water phases, including the effect of temperature in the liquid [2]. These experiments stirred a storm of controversy because of their interpretation suggesting that a large fraction (>80%) of H-bonds are broken in the liquid [2]. This would imply an environment consisting primarily of chains and rings of H-bonds, in stark contrast with the conventional near-tetrahedral picture supported by diffraction [3] and other thermodynamic and spectroscopic data [4,5]. The broken H-bond fraction was estimated from the intensity of the pre-edge, which is prominent in the liquid and was believed to be absent in bulk ice. Subsequent x-ray Raman spectra, however, showed that the pre-edge feature is present, albeit with different intensity, not only in the liquid, but also in hexagonal (Ih), cubic (Ic), low-density amorphous (LDA) and highdensity amorphous (HDA) ice [6]. This experiment reported another interesting observation, namely that water and HDA ice have spectra with the main-edge more prominent than the post-edge, while the opposite behavior occurs in Ih, Ic, and LDA ice. This is puzzling given that both LDA and HDA ice are disordered structures with an insignificant fraction of broken H-bonds. Spectral calculations, based on electronic density-functional theory (DFT) and near-tetrahedral liquid models, correctly predicted the presence of three spectral features in ice and water and associated the enhancement of the pre-edge intensity to broken H-bonds [7,8,9,10]. However, the agreement with experiment was only semiquantitative and the calculations did not identify the cause of the significant changes in main-and post-edge spectra. These effects were generically attributed to disorder [8], but this does not explain why LDA and HDA ice show opposite behavior [6]. Finally, no attempt was made to discuss the effect of temperature in the liquid spectra, for which contrasting experimental data have been reported [2,11,12,13].In this paper we use liquid structures generated by ab-initio MD to compute x-ra...

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Ab InitioCalculation of Optical Spectra of Liquids: Many-Body Effects in the Electronic Excitations of Water

Cited by 81 publications

References 31 publications

Communication: Electronic structure of the solvated chloride anion from first principles molecular dynamics

Communication: Electronic structure of the solvated chloride anion from first principles molecular dynamics

Optical properties of bulk semiconductors and graphene/boron nitride: The Bethe-Salpeter equation with derivative discontinuity-corrected density functional energies

X-Ray Absorption Signatures of the Molecular Environment in Water and Ice

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