Far-infrared spectra of the tryptamine A conformer by IR-UV ion gain spectroscopy.

We present far infrared spectra of the conformer A of tryptamine in the 200 to 500 cm wavenumber range along with resonant photoionization spectra of the far-infrared excited conformer A of tryptamine. We show that single-far-infrared photon excited tryptamine has highly structured resonance enhanced multi-photon ionization spectra, revealing the mode composition of the S-state. Upon multiple-far-infrared photon absorption, the resonance enhanced multi-photon ionization spectrum broadens allowing ion gain spectroscopy to be performed.

A theoretical and experimental study of pressure broadening of the oxygen A-band by helium.

The rotationally resolved magnetic dipole absorption spectrum of the oxygen A-band b(1)Σ(g)(+)(v=0) <- X(3)Σ(g)(-)(v=0) perturbed by collisions with helium was studied theoretically using the impact approximation. To calculate the relaxation matrix, scattering calculations were performed on a newly computed helium-oxygen (b(1)Σ(g)(+)) interaction potential as well as on a helium-oxygen (X(3)Σ(g)(-)) interaction potential from the literature. The calculated integrated line cross sections and broadening coefficients are in good agreement with experimental results from the literature.

Collision induced absorption in the a1Δ(v = 2) ← X3Σg(-)(v = 0) band of molecular oxygen.

Using cavity ring-down spectroscopy we measured the collision induced absorption spectrum associated with the a(1)Δ(v = 2) ←X(3)Σ(g)(-)(v = 0) band of oxygen near 922 nm both in pure oxygen and in mixtures of oxygen and nitrogen. For pure oxygen, we report for this band an integrated absorption of (1.56 - 0.

Collision-induced absorption in the O2 B-band region near 670 nm.

We have determined the collision-induced absorption (CIA) spectrum in the O(2) B-band in pure oxygen. We present absolute extinction coefficients of the minimums in between rotational lines using cavity ring-down spectroscopy. The measured extinction is corrected for the B-band magnetic dipole absorption using a model which includes line-mixing.

Line mixing and collision induced absorption in the oxygen A-band using cavity ring-down spectroscopy.

This paper reports on the absorption of molecular oxygen in the region of the A-band near 760 nm under atmospheric conditions relevant for satellite retrieval studies. We use pulsed laser cavity ring-down spectroscopy with a narrow bandwidth laser and use pressure scans to increase the accuracy of the measured oxygen extinction coefficients. Absolute binary absorption coefficients in minima between absorption lines of the A-band spectrum have been measured and tabulated.