scholarly journals Characterization of gas-phase HCl-H 2 O clusters using pulsed infrared cavity ringdown spectroscopy

2002 ◽  
Author(s):  
Alex J. Huneycutt ◽  
Ross J. Stickland ◽  
F. Hellberg ◽  
Richard J. Saykally
2020 ◽  
Vol 74 (4) ◽  
pp. 408-416
Author(s):  
Yoshiteru Matsumoto ◽  
Souichi Tezuka

Two-dimensional correlation spectroscopy (2D-COS) is a useful technique to analyze any intensity behavior of optical spectra that exhibit a complicated feature with overlapped bands. In this study, we apply 2D-COS to the infrared (IR) spectra of gas-phase pyrrole (Py) clusters. The NH stretching vibrations of the Py clusters are measured by cavity ringdown spectroscopy. The observed IR spectra of the Py clusters consist of sharp bands, full width half-maximum (FWHM) ∼1 cm−1, and a broad background (FWHM >50 cm−1). The 2D asynchronous correlation spectra reveal that the sharp bands and a broad background are assigned to small clusters of dimer to pentamer and large clusters with bulk-like structures, respectively, which support the results of our previous study. The sharp bands are also analyzed using another 2D asynchronous correlation spectrum, which is obtained by decomposing the observed IR spectra into sharp and broad components. Because the asynchronous signals are consistent with those obtained from the IR spectra without decomposition, the result would suggest that we need not to decompose the IR spectra into sharp and broad components before applying 2D-COS. However, our model simulations of 2D-COS showed a counterexample that gives an incorrect result without removing a broad background component from the IR spectra. This study strongly suggests that we need to undertake a careful treatment of the complicated IR spectrum with various widths of bands.


2013 ◽  
Vol 9 (S297) ◽  
pp. 237-246 ◽  
Author(s):  
L. N. Zack ◽  
J. P. Maier

AbstractCarriers of the diffuse interstellar bands (DIBs) cannot be definitively identified without laboratory spectra. Several techniques, including matrix isolation, cavity ringdown spectroscopy, resonance enhanced multiphoton ionization, and ion trapping, have been used to measure the electronic spectra of carbon chains and their derivatives. The gas-phase laboratory spectra could then be compared to the astronomical data of known DIBs. The choice of molecules studied in the gas phase depends on the presence of strong electronic transitions at optical wavelengths, the lifetimes of excited electronic states, and chemical feasibility in diffuse astrophysical environments. Collisional-radiative rate models have also be used in conjunction with laboratory spectra to predict absorption profiles under interstellar conditions.


2004 ◽  
Vol 82 (6) ◽  
pp. 848-853 ◽  
Author(s):  
Mitsunori Araki ◽  
Pawel Cias ◽  
Alexey Denisov ◽  
Jan Fulara ◽  
John P Maier

The electronic spectrum of a nonlinear carbon chain radical C4H4+ was observed after mass-selective deposition in a 6 K neon matrix. The corresponding gas-phase spectra of C4H4+ and C4D4+ have been observed in the 512 to 513 nm region and at 710 nm for C8H4+. These were detected in direct absorption by cavity ringdown spectroscopy through a supersonic planar discharge. The electronic transition energies of these nonlinear carbon chain radicals correlate well with those of the polyacetylene cations HCnH+ (n = 4, 6, 8). The observed profiles are reproduced with rotational constants obtained by ab initio geometry optimizations and extrapolation between the ground and excited electronic states. Key words: nonlinear carbon chain, carbon cation, electronic transition, diffuse interstellar bands, molecular structure.


1998 ◽  
Vol 120 (49) ◽  
pp. 12956-12957 ◽  
Author(s):  
C. J. Chapo ◽  
J. B. Paul ◽  
R. A. Provencal ◽  
K. Roth ◽  
R. J. Saykally

2000 ◽  
Vol 112 (24) ◽  
pp. 10695-10698 ◽  
Author(s):  
Michael B. Pushkarsky ◽  
Sergey J. Zalyubovsky ◽  
Terry A. Miller

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