Overtone and Combination Band Spectroscopy of H₃⁺

Table of Contents

Title Page

About H3+

Importance of H3+

Why Study High Energy H3+?

H3+ Vibrational Bands

Experimental Technique

New Focus Diode Laser

Plasma Conditions

New Focus "Nirvana" Detector

Theoretical Predictions

Predictions for nu1+2nu2(0)

Lines Studied to Date

Representative Spectrum

H2 Rydberg Transitions

Summary of Detections

Future Work

nu1+2nu2(2) Band Intensities

Email: bjmccall@astro.berkeley.edu

Home Page: http://astro.berkeley.edu/~bjmccall

Other information:
Presented at the 53rd Ohio State University International Symposium on Molecular Spectroscopy, 1998, talk RD02. [15 minutes]

Abstract: We report our detection of H₃⁺ rovibrational transitions between 7700 and 8200 cm-1. This work employed a New Focus external cavity tunable diode laser, a positive column discharge, and the velocity modulation technique for enhanced sensitivity to molecular ions. This frequency range encompasses transitions of the 3nu2(1) <- 0 and nu1 + 2nu2 <- 0 bands -- the highest energy transitions studied to date.
As the simplest three-atom molecule, H₃⁺ has long served as a benchmark for ab initio calculations. We have compared our observed frequencies with our predictions, and expect that this work (along with detection of even higher overtones) will lead to better ab initio treatments of this important molecule.

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