Molecular Spectroscopy: A Study of Molecules in Earth and Planetary Atmospheres

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The four most abundant isotopologues (N2O, 15NNO, N15NO, and NN18O) of nitrous oxide have been measured in the Earth's atmosphere by infrared remote sensing with the Atmospheric Chemistry Experiment (ACE) Fourier transform spectrometer. These satellite observations have provided a near global picture of N2O isotopic fractionation. The relative abundance of the heavier isotopologues increase with altitude and with latitude in the stratosphere as the air becomes older. Near global 85°S{85°N atmospheric measurement of carbonyl sulfide (OCS), including the minor OC34S and O13CS isotopologues, were made by the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) in low Earth orbit. ACE-FTS data provide volume mixing ratio (VMR) profiles of OCS, OC34S and O13CS from 8 km in the troposphere up to 31 km in the stratosphere. The global zonal and seasonal distributions of OCS isotopologues were studied. OCS observations made with the MkIV balloon-borne Fourier transform spectrometer (FTS) are also presented. The results indicate a slight enrichment of OC34S and a significant enrichment of O13CS as the altitude increases. The contribution of OCS to the background Stratospheric Sulfate Aerosol Layer (SSA) is discussed and ACE-FTS data indicate that OCS is a major contributor. Vibration-rotation line lists for AlF, Al35Cl and Al37Cl have been prepared in their ground electronic states (X1Σ+). Experimental rotational and ro-vibrational lines were employed to calculate a potential energy surface (PES) by direct potential fit-ting. The PES was used to calculate ro-vibrational energy levels. Born-Openheimer Breakdown (BOB) corrections were included in the energy level calculations for AlCl. Ro-vibrational energy levels were calculated for the v=0 to v=11 vibrational levels and up to Jmax =200 for the rotational levels. Dipole moment functions (DMFs) covering the range of the PES turning points were calculated for AlCl and AlF by ab initio methods and used to determine line intensities. Partition functions for temperatures up to 3000 K were calculated. AlF and AlCl have been detected in circumstellar envelopes and are predicted to occur in cool stellar and sub-stellar atmospheres. A new line list for the A2Σ+X2Π electronic transition of OH has been calculated. Line positions have been taken from the literature and refitted with Western's PGOPHER program. Line intensities were calculated using a new ab initio Transition Dipole Moment Function (TDMF) obtained with Molpro 2012. The new TDMF and the potential functions from LeRoy's RKR program have been used as input to LeRoy's LEVEL program in order to calculate Transition Dipole Moment Matrix Elements (TDMMEs). These matrix elements were transformed from Hund's case (b) to Hund's case (a) as required for the PGOPHER program. The line list…