include "format.php"; ?>
| ||||||
include "leftnav.php"; ?> |
This question led me into a fruitful collaboration with Mats Larsson at Stockholm University and Alex Huneycutt (a graduate student in Rich Saykally's group). Because we often use supersonic expansion discharges to produce cold ions for laboratory spectroscopy, we decided to adapt this technology for storage-ring measurements of H3+ DR. In Berkeley, we developed a supersonic ion source for H3+ and spectroscopically characterized it using cavity ringdown laser absorption spectroscopy [using a YAG-pumped dye laser which was Raman shifted into the infrared using gaseous hydrogen]. By probing the H3+ fundamental band, we confirmed that this source produced ions with a rotational temperature of ~30 K. We then took this source to the CRYRING ion-storage ring at the Manne Siegbahn Laboratory in Stockholm, where we performed dissociative recombination cross-section measurements. These measurements provide the first direct measurement of the H3+ dissociative recombination rate under "interstellar conditions," and have ruled out a very low value of this rate coefficient as the cause of the overabundant H3+ in diffuse clouds.
Reference:
|