Cold-surface photochemistry of selected organic nitrates.

Reflection-absorption infrared (RAIR) spectroscopy has been used to explore the low temperature condensed-phase photochemistry of atmospherically relevant organic nitrates for the first time. Three alkyl nitrates, methyl, isopropyl, and isobutyl nitrate together with a peroxyacyl nitrate, peroxyacetyl nitrate (PAN), were examined. For the alkyl nitrates, similar photolysis products were observed whether they were deposited neat to the gold substrate or codeposited with water.

Investigation of terahertz vibration-rotation tunneling spectra for the water octamer.

We report a combined theoretical and experimental study of the water octamer-h16. The calculations used the ring-polymer instanton method to compute tunnelling paths and splittings in full dimensionality. The experiments measured extensive high resolution spectra near 1.

Cold-surface photochemistry of primary and tertiary alkyl nitrites.

Reflection-absorption infrared spectroscopy (RAIRS) is used to explore the photochemistry of primary and tertiary alkyl nitrites deposited on a gold surface. The primary alkyl nitrites examined for this study were n-butyl, isobutyl, and isopentyl nitrite. These compounds showed qualitatively similar spectra to those observed in previous condensed-phase measurements.

Vibrational analysis of n-butyl, isobutyl, sec-butyl and tert-butyl nitrite.

Raman and infrared spectra of n-butyl, isobutyl, sec-butyl and tert-butyl nitrite are reported. Density functional theory and Møeller-Plesset calculations with 6-31G* and 6-311G* basis sets were used to determine ground state molecular geometries and vibrational frequencies of these compounds. Calculations and spectral data of these molecules were used to perform partial vibrational mode assignments for the observed transitions.

Water pentamer: characterization of the torsional-puckering manifold by terahertz VRT spectroscopy.

We present the measurement and analysis of five new (D2O)5 bands via vibration-rotation-tunneling (VRT) spectroscopy as well as a preliminary description of a second (H2O)5 band. The vibrationally averaged rotational constants of all five fitted bands agree well with those from the two previously observed (D2O)5 bands and confirm that the pentamer averages to a symmetric, quasi-planar structure on the time scale of our experiment. While the spectrum of the first two bands, located at 50.

Vibrational analysis of isopropyl nitrate and isobutyl nitrate.

Raman and infrared spectra of isopropyl nitrate and isobutyl nitrate are reported. These spectra are used in combination with computational studies employing density functional theory at the B3-LYP/6-31G* level to assign the vibrational transitions to their corresponding normal coordinates. Similar to other alkyl nitrates, the frequency of the NO2 symmetric stretch remains relatively unchanged while the asymmetric stretch shifts to lower frequency with increasing alpha-carbon substitution.