27-10-2012, 02:05 PM
Precise Laboratory Measurement of Line Frequencies Useful to Studies of Star and Planet Formation
ABSTRACT
In March 2002, we began a program in laboratory spectroscopy to provide accurate molecular line frequencies essential
to studies of the motions and abundance in star-forming dense cores and planet-forming circumstellar disks. Summarized here
is the progress that has been made in Year 3 of this grant. Work included measurement of 10 successive rotational lines in the
ground vibrational state of SiO between 86 and 500 GHz, and two lines near 800 GHz to an accuracy of a few kHz; conducting
pilot experiments on molecular ions in collision-free supersonic beams, including HCO+, N2H+, and H2D+; measurement of
22 lines of CN between 113 and 340 GHz; and setting up an experiment that would allow us to refine earlier measurements
of the neutral species such as C3H2, CCS, H2CS, and SO by observing the very narrow sub-Doppler (Lamb dip) features in
the millimeter-wave spectra of these species.