State-to-State Rate Coefficients for NH-NH Collisions from Pump-Probe Chirped Pulse Experiments.

The kinetics of rotational inelastic NH-NH collisions are recorded using pump-probe experiments, carried out with a K-band waveguide chirped pulse Fourier transform microwave spectrometer, in which the population of one inversion doublet is altered by the pump pulse. Due to self-collisions, the resulting deviation from equilibrium propagates to other states and, thus, can be interrogated by probe pulses as a function of the pump-probe delay time. A clear hierarchy of the state-to-state collision processes is found and subsequently translated into propensity rules.

High-resolution spectroscopy of C3 around 3 μm.

We report on the detection of the (10(0)1) ← (00(0)0) vibrational band of gas-phase C3 and the two of its mono (13)C substituted isotopologs in the infrared region around 3200 cm(-1). Additionally, the associated hot band (11(1)1) ← (01(1)0) has been assigned for the parent isotopolog. Spectra have been recorded using a supersonic jet spectrometer with a laser ablation source in combination with a continuous-wave optical parametric oscillator as radiation source.

Submillimeter-wave and far-infrared spectroscopy of high-J transitions of the ground and ν2 = 1 states of ammonia.

Complete and reliable knowledge of the ammonia spectrum is needed to enable the analysis and interpretation of astrophysical and planetary observations. Ammonia has been observed in the interstellar medium up to J=18 and more highly excited transitions are expected to appear in hot exoplanets and brown dwarfs. As a result, there is considerable interest in observing and assigning the high J (rovibrational) spectrum.