Abstract
The millimeter-wave spectrum of the CaH and CaD radicals (X2Σ+) has been observed in the laboratory via direct absorption spectroscopy. The species were generated by the reaction of calcium vapor, produced in a Broida-type oven, with hydrogen atoms created in a microwave discharge. The six hyperfine components of the N = 0 → 1 rotational transition of CaH near 254 GHz were resolved and their frequencies determined to an accuracy of ± 100 kHz. The main hyperfine lines originating in the N = 0 → 1, 1 → 2, and 2 → 3 rotational transitions of CaD were also detected. Spectroscopic constants were determined for both radicals from a nonlinear least squares fit to the data, using a 2Σ Hamiltonian. These measurements constitute the first laboratory observation of CaH at high spectral resolution, and are essential to the detection of this radical in interstellar space.
Original language | English (US) |
---|---|
Pages (from-to) | L65-L67 |
Journal | Astrophysical Journal |
Volume | 408 |
Issue number | 1 PART 2 |
DOIs | |
State | Published - 1993 |
Externally published | Yes |
Keywords
- ISM: Molecules
- Line: Identification
- Molecular data
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science