Vibrational spectra of vapor-phase dimethylamine (DMA) and pyrrole have been recorded in the 1000 to 13000 cm(-1) region using long path conventional spectroscopy techniques. We have focused on the absolute intensities of the NH-stretching fundamental and overtone transitions; Δν(NH) = 1-4 regions for DMA and the Δν(NH) = 1-3 regions for pyrrole. In the Δν(NH) = 1-3 regions for DMA, evidence of tunneling splitting associated with the NH-wagging mode is observed. For DMA, the fundamental NH-stretching transition intensity is weaker than the first NH-stretching overtone. Also, the fundamental NH-stretching transition in DMA is much weaker than the fundamental transition in pyrrole. We have used an anharmonic oscillator local mode model with ab initio calculated local mode parameters and dipole moment functions at the CCSD(T)/aug-cc-pVTZ level to calculate the NH-stretching intensities and explain this intensity anomaly in DMA.

Vibrational spectra of vapor-phase 1,2-ethanedithiol and 2-mercaptoethanol were recorded to investigate weak intramolecular interactions. The spectra were recorded with conventional absorption spectroscopy and laser photoacoustic spectroscopy in the 2000-11,000 cm(-1) region. The room temperature spectra of each molecule are complicated by contributions from several conformers. Anharmonic oscillator local-mode calculations of the OH- and SH-stretching transitions have been performed to facilitate assignment of the different conformers in the spectra. We observe evidence of hydrogen-bond-like interactions from OH to S, but not from SH to O or S. The OH to S intramolecular interaction in 2-mercaptoethanol is weak and comparable to that found in the OH to O interaction in ethylene glycol.

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Polar amplification (PA) refers to the phenomenon where an external radiative forcing, such as changes in greenhouse gases (GHGs) and solar variability (Collins et al., 2013;Gregory & Webb, 2007;Gregory et al., 2004) causes a stronger warming effect in the polar regions than the rest of the Earth (Manabe & Wetherald, 1975;Trenberth et al., 2007). PA can be quantified by the PA factor (fPA) which is the ratio between temperature change in the high latitudes to the temperature change in the low-to mid-latitudes. PA is a key aspect of climate change, but its causes and effects are still not fully understood. Fundamentally, PA depends on variations in the temperature sensitivity to external forcings across different regions of the Earth. An amplified warming in high latitudes results in a smaller meridional temperature gradient between the equator and the poles. The meridional temperature gradient between low and high latitudes governs many features of the dynamics in the atmosphere, such as the meridional heat transport associated with large scale circulations, atmospheric winds via the thermal