Analyzing the n&lt;FONT FACE=Symbol&gt;®p&lt;/FONT&gt;* electronic transition of formaldehyde in water: a sequential Monte Carlo/time-dependent density functional theory

Malaspina, Thaciana; Coutinho, Kaline; Canuto, Sylvio

doi:10.1590/s0103-50532008000200017

Cited by 5 publications

(11 citation statements)

References 39 publications

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“…The spectra are likely to retain the properties of a single formaldehyde solvated molecule. 7,9,[11][12][13][14][15][16] Thus, these experimental findings are consistent with a solvent blue-shift effect. Ab initio Car-Parrinello (CP) molecular dynamics (MD) and hybrid CPMD/MM calculations in conjunction with techniques for excited states such as time-dependent density functional theory (TDDFT) 24,25 are mature techniques to study electronic absorption spectra of solutes in water at room temperature.…”

Section: Introductionsupporting

confidence: 83%

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

Lupieri

Ippoliti

Altoè

et al. 2010

J. Chem. Theory Comput.

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We present Car-Parrinello and Car-Parrinello/molecular mechanics simulations of the structural, vibrational, and electronic properties of formaldehyde in water. The calculated properties of the molecule reproduce experimental values and previous calculations. The n → π* excitation energy, calculated with TDDFT and CASPT2, agrees with experimental data. In particular, it shows a blue shift on going from the gas phase to aqueous solution. Temperature and wave function polarization contributions have been disentangled.

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Section: Introductionsupporting

confidence: 83%

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

Lupieri

Ippoliti

Altoè

et al. 2010

J. Chem. Theory Comput.

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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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“…Many studies follow a similar scheme. [31][32][33][34][35] Sanchez et al used classical MD simulation to calculate the averaged value of the solvent electrostatic potential and perform quantum mechanical calculations using this averaged mean field. 36 This reduces the number of quantum mechanical calculations; however, it cannot construct the entire spectrum.…”

Section: Introductionmentioning

confidence: 99%

Solvent effect on the absorption spectra of coumarin 120 in water: A combined quantum mechanical and molecular mechanical study

Sakata

Kawashima

Nakano

2011

The Journal of Chemical Physics

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The solvent effect on the absorption spectra of coumarin 120 (C120) in water was studied utilizing the combined quantum mechanical∕molecular mechanical (QM∕MM) method. In molecular dynamics (MD) simulation, a new sampling scheme was introduced to provide enough samples for both solute and solvent molecules to obtain the average physical properties of the molecules in solution. We sampled the structure of the solute and solvent molecules separately. First, we executed a QM∕MM MD simulation, where we sampled the solute molecule in solution. Next, we chose random solute structures from this simulation and performed classical MD simulation for each chosen solute structure with its geometry fixed. This new scheme allowed us to sample the solute molecule quantum mechanically and sample many solvent structures classically. Excitation energy calculations using the selected samples were carried out by the generalized multiconfigurational perturbation theory. We succeeded in constructing the absorption spectra and realizing the red shift of the absorption spectra found in polar solvents. To understand the motion of C120 in water, we carried out principal component analysis and found that the motion of the methyl group made the largest contribution and the motion of the amino group the second largest. The solvent effect on the absorption spectrum was studied by decomposing it in two components: the effect from the distortion of the solute molecule and the field effect from the solvent molecules. The solvent effect from the solvent molecules shows large contribution to the solvent shift of the peak of the absorption spectrum, while the solvent effect from the solute molecule shows no contribution. The solvent effect from the solute molecule mainly contributes to the broadening of the absorption spectrum. In the solvent effect, the variation in C-C bond length has the largest contribution on the absorption spectrum from the solute molecule. For the solvent effect on the absorption spectrum from the solvent molecules, the solvent structure around the amino group of C120 plays the key role.

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Analyzing the n<FONT FACE=Symbol>®p</FONT>* electronic transition of formaldehyde in water: a sequential Monte Carlo/time-dependent density functional theory

Cited by 5 publications

References 39 publications

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

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

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

Solvent effect on the absorption spectra of coumarin 120 in water: A combined quantum mechanical and molecular mechanical study

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