The lower electronic states of nitrite and nitrate ion, nitromethane, nitramide, nitric acid, and nitrate esters

Harris, L. E.

doi:10.1063/1.1679185

Cited by 106 publications

(44 citation statements)

References 25 publications

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“…25,54 The LUMO is a π* antibonding orbital, with a large contribution of 2p z atomic orbitals of oxygen and nitrogen atoms from the nitro-group and a relatively small contribution of 2p z atomic orbitals from the ester oxygen atom (Figure 2). …”

Section: Ethyl Nitrate As a Model Moleculementioning

confidence: 99%

Energies of Electronic Transitions of Pentaerythritol Tetranitrate Molecules and Crystals

2014

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Despite significant effort in research on energetic nitrocompounds coupled with a great interest in these materials for a range of technological and medical applications, the electronic structure of condensed energetic materials is barely studied. In this research aimed at a better understanding of the low energy absorption in the optical spectrum of nitro-compounds, the electronic structure and vertical electronic transitions of a gas-phase pentaerythritol tetranitrate (PETN) molecule and an ideal PETN crystal were explored by means of density functional theory based calculations. In accordance with most experimental observations, the optical absorption spectrum of PETN has a well-resolved intense band above 6 eV that is accompanied by a few low intensity broad bands at lower energies. Our modeling suggests that the high intensity band corresponds to a series of strong singlet−singlet transitions, while the lower energy bands are attributed to the formation of tightly bound singlet and triplet excitons. All transitions are well-localized on O−NO 2 groups of PETN. We also systematically analyze low energy excitations in other nitro-compounds, which exhibit similar patterns in the spectra even though the experimental data are incomplete at the moment. We predict that tightly bound excitons and charge transfer excitons should exist in PETN and both would trigger the nitrate decomposition, which allows for precise control of the initiation process.

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Section: Ethyl Nitrate As a Model Moleculementioning

confidence: 99%

Energies of Electronic Transitions of Pentaerythritol Tetranitrate Molecules and Crystals

2014

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“…These molecules have NANO 2 bonds, characteristic of widely used energetic materials with the very labile NO 2 group easily withdrawn. In addition, compounds having NO 2 groups have broad electronic spectra, tendency to dissociation, and trigger different photochemical phenomena [9], a picture calling for theoretical works on these systems.…”

Section: Introductionmentioning

confidence: 99%

Electronic spectra of nitroethylene

Borges

Barbatti

Aquino

et al. 2011

Int J of Quantum Chemistry

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A systematic study of the electronic excited states of nitroethylene (C₂H₃NO₂) was carried out using the approximate coupled-cluster singles-and-doubles approach with the resolution of the identity (RI-CC2), the time dependent density functional theory with the CAMB3LYP functional (TDDFT/CAMB3LYP) and the DFT multireference configuration interaction (DFT/MRCI) method. Vertical transition energies and optical oscillator strengths were computed for a maximum of 20 singlet transitions. Semiclassical simulations of the ultraviolet (UV) spectra were performed at the RI-CC2 and DFT/MRCI levels. The main features in the UV spectrum were assigned to a weak n-π* transition, and two higher energy π_CC+O−π* bands. These characteristics are common to molecules containing NO2 groups. Simulated spectra are in good agreement with the experimental spectrum. The energy of the bands in the DFT/MRCI simulation agrees quite well with the experiment, although it overestimates the band intensities. RI-CC2 produced intensities comparable to the experiment, but the bands were blue shifted. A strong π_CC+O−π* band, not previously measured, was found in the 8–9 eV range

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“…I now focus on the two competing mechanisms, previously misassigned (73,78), for fission of the N-OH bond to form OH + NO 2 . The π nb,O → π * NO 2 excitation at 193 nm accesses the 2 1 A excited state potential energy surface of nitric acid, which has local B 2 electronic symmetry at the nitro group (79,80 1 }. This is exactly the kind of electronic change along an adiabatic reaction coordinate that makes the reaction subject to nonadiabatic effects; the individual NO 2 orbital symmetries change from a a in the reactant region to a a in the product region along the 2 1 A excited-state potential energy surface (the adiabatic reaction products are Woodward-Hoffmann forbidden).…”

Section: Conformational Dependence Of Nonadiabatic Recrossing and Itsmentioning

confidence: 99%

Chemical Reaction Dynamics Beyond the Born-Oppenheimer Approximation

Butler

1998

Annu. Rev. Phys. Chem.

233

172

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To predict the branching between energetically allowed product channels, chemists often rely on statistical transition state theories or exact quantum scattering calculations on a single adiabatic potential energy surface. The potential energy surface gives the energetic barriers to each chemical reaction and allows prediction of the reaction rates. Yet, chemical reactions evolve on a single potential energy surface only if, in simple terms, the electronic wavefunction can evolve from the reactant electronic configuration to the product electronic configuration on a time scale that is fast compared to the nuclear dynamics through the transition state. The experiments reviewed here investigate how the breakdown of the BornOppenheimer approximation at a barrier along an adiabatic reaction coordinate can alter the dynamics of and the expected branching between molecular dissociation pathways. The work reviewed focuses on three questions that have come to the forefront with recent theory and experiments: Which classes of chemical reactions evidence dramatic nonadiabatic behavior that influences the branching between energetically allowed reaction pathways? How do the intramolecular distance and orientation between the electronic orbitals involved influence the nonadiabaticity in the reaction? How can the detailed nuclear dynamics mediate the effective nonadiabatic coupling encountered in a chemical reaction?

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The lower electronic states of nitrite and nitrate ion, nitromethane, nitramide, nitric acid, and nitrate esters

Cited by 106 publications

References 25 publications

Energies of Electronic Transitions of Pentaerythritol Tetranitrate Molecules and Crystals

Energies of Electronic Transitions of Pentaerythritol Tetranitrate Molecules and Crystals

Electronic spectra of nitroethylene

Chemical Reaction Dynamics Beyond the Born-Oppenheimer Approximation

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