relation: http://d-scholarship-dev.library.pitt.edu/17251/
title: Solid state and solution nitrate photochemistry: Photochemical evolution of the solid state lattice
creator: Asher, SA
creator: Tuschel, DD
creator: Vargson, TA
creator: Wang, L
creator: Geib, SJ
description: We examined the deep UV 229 nm photochemistry of NaNO3 in solution and in the solid state. In aqueous solution excitation within the deep UV NO3- strong π → π* transition causes the photochemical reaction NO3- → NO2- + O·. We used UV resonance Raman spectroscopy to examine the photon dose dependence of the NO2- band intensities and measure a photochemical quantum yield of 0.04 at pH 6.5. We also examined the response of solid NaNO3 samples to 229 nm excitation and also observe formation of NO2-. The quantum yield is much smaller at ∼10-8. The solid state NaNO3 photochemistry phenomena appear complex by showing a significant dependence on the UV excitation flux and dose. At low flux/dose conditions NO2- resonance Raman bands appear, accompanied by perturbed NO3- bands, indicating stress in the NaNO3 lattice. Higher flux/dose conditions show less lattice perturbation but SEM shows surface eruptions that alleviate the stress induced by the photochemistry. Higher flux/dose measurements cause cratering and destruction of the NaNO3 surface as the surface layers are converted to NO2-. Modest laser excitation UV beams excavate surface layers in the solid NaNO3 samples. At the lowest incident fluxes a pressure buildup competes with effusion to reach a steady state giving rise to perturbed NO3- bands. Increased fluxes result in pressures that cause the sample to erupt, relieving the pressure. © 2011 American Chemical Society.
date: 2011-05-05
type: Article
type: PeerReviewed
format: text/plain
language: en
rights: attached
identifier: http://d-scholarship-dev.library.pitt.edu/17251/1/licence.txt
identifier:   Asher, SA and Tuschel, DD and Vargson, TA and Wang, L and Geib, SJ  (2011) Solid state and solution nitrate photochemistry: Photochemical evolution of the solid state lattice.  Journal of Physical Chemistry A, 115 (17).  4279 - 4287.  ISSN 1089-5639     
relation: 10.1021/jp200406q