Spectroscopic Properties of Formaldehyde in Aqueous Solution: Insights from Car−Parrinello and TDDFT/CASPT2 Calculations

Lupieri, Paola; Ippoliti, Emiliano; Altoè, Piero; Garavelli, Marco; Mwalaba, M.; Carloni, Paolo

doi:10.1021/ct100384f

Cited by 8 publications

(3 citation statements)

References 80 publications

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“…It is well-known that the first excitation of formaldehyde (nπ*) is blue-shifted in bulk water, and experimentally, the shift has been estimated to be 23 nm (although this value is not conclusive because of the marked trend of formaldehyde to aggregate). Solvent effects on this electronic transition have also been discussed with various theoretical approaches. − In this work, we have calculated the statistical averages of the absorption wavelengths λ and oscillator strengths f for the first three excited states. As shown in Table , the excitations at the air/water interface display substantial differences with respect to gas phase.…”

Section: Resultsmentioning

confidence: 99%

Reactivity of Volatile Organic Compounds at the Surface of a Water Droplet

et al. 2012

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Knowledge of the role of water droplets and aerosols in atmospheric chemistry is crucial to significantly improve our understanding of global warming and air quality. Chemistry at the air/water interface, in particular, is still poorly understood. There is a great need to understand how clouds and aerosols process chemistry of organics prevalent in the atmosphere. We report in this study the first computer simulation of a volatile organic compound (formaldehyde) at the air/water interface with explicit description of its ground and excited states electronic properties. We use an elaborated technique that combines molecular dynamics simulations together with a quantum/classical description of the formaldehyde-water system. We show that in spite of a large affinity for water, formaldehyde exhibits a preference for the air/water interface with respect to the bulk, roughly by 1.5 kcal/mol. Another important finding in our simulations is that frontier orbitals HOMO and LUMO undergo substantial stabilization at the interface due to surface water reorientation, which induces a local positive electrostatic potential. Such a potential is significantly larger than the one estimated in bulk water suggesting that the reactivity of formaldehyde could change with respect to both gas phase and bulk water. The conclusions presented in this work are expected to help/guide future experiments studying the chemical reactivity of volatile organic compounds at the air/water interface.

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Section: Resultsmentioning

confidence: 99%

Reactivity of Volatile Organic Compounds at the Surface of a Water Droplet

et al. 2012

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“…Indeed, QM/MM methods have also been explored for excited-state dynamics governing photochemical reactions. 242,[253][254][255][256]261,[263][264][265][266][267][268][269] DFT for ground states or time-dependent DFT (TD-DFT) 270 for the description of electronically excited states are computationally very efficient and have been used successfully, in particular in conjunction with Car-Parrinello MD methods 243,249,250,[271][272][273][274][275] including non-adiabatic dynamics. 251,265,266,[276][277][278][279] Nevertheless, the quality of results obtained by TD-DFT calculations depends on the system under investigation and on the functional used to reproduce the exchange and correlation interactions.…”

Section: Excited Statesmentioning

confidence: 99%

Chapter 9. First Principles Methods in Biology: From Continuum Models to Hybrid Ab initio Quantum Mechanics/Molecular Mechanics

Dreyer¹,

Brancato²,

Ippoliti³

et al. 2016

Theoretical and Computational Chemistry Series

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“…This approach has been shown to give fairly good results for a variety of solutes in aqueous solution. [22][23][24][25][26]…”

Section: Introductionmentioning

confidence: 99%

Structural prediction of a rhodamine-based biosensor and comparison with biophysical data

Gonçalves

Dreyer

Lupieri

et al. 2013

Phys. Chem. Chem. Phys.

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The predicted structure has been calculated for a protein-based biosensor for inorganic phosphate (Pi), previously developed by some of us (Okoh et al., Biochemistry, 2006, 45, 14764). This is the phosphate binding protein from Escherichia coli labelled with two rhodamine fluorophores. Classical molecular dynamics and hybrid Car-Parrinello/molecular mechanics simulations allow us to provide molecular models of the biosensor both in the presence and in the absence of Pi. In the latter case, the rhodamine fluorophores maintain a stacked conformation in a 'face A to face B' orientation, which is different from the 'face A to face A' stacked orientation of free fluorophores in aqueous solution (Ilich et al., Spectrochim. Acta, Part A, 1996, 52, 1323). A protein conformation change upon binding Pi prevents significant stacking of the two rhodamines. In both states, the rhodamine fluorophores form hydrophobic contact with LEU291, without establishing significant hydrogen bonds with the protein. The accuracy of the models is established by a comparison between calculated and experimental absorption and circular dichroism spectra.

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Spectroscopic Properties of Formaldehyde in Aqueous Solution: Insights from Car−Parrinello and TDDFT/CASPT2 Calculations

Cited by 8 publications

References 80 publications

Reactivity of Volatile Organic Compounds at the Surface of a Water Droplet

Reactivity of Volatile Organic Compounds at the Surface of a Water Droplet

Chapter 9. First Principles Methods in Biology: From Continuum Models to Hybrid Ab initio Quantum Mechanics/Molecular Mechanics

Structural prediction of a rhodamine-based biosensor and comparison with biophysical data

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