15min:

K. KAWAGUCHI, N. SANECHIKA, Y. NISHIMURA, R. FUJIMORI, Faculty of Science, Okayama University, Okayama 700-8530, Japan; T. N. OKA, Y. HIRAHARA, Graduate School of Environmental Studies, Chikusa, Nagoya, 464-8601, Japan; A. I. JAMAN, Saha Institute of Nuclear Physics, Bidhannagar, Kolkata -700 064, India; AND S. CIVIS, J. Heyrovsky Institute of Physical Chemistry, Dolejskova 3, 18223 Prague 8, Czech Republic.

Time-resolved Fourier transform infrared spectroscopy was applied for observations of emission spectra from Nd:YLF laser ablation products. A high-repetition rate laser (Photonics Industry DM10-527, 2.5 kHz) with 1-2 mJ output power was focused on a rotating rod of metal and carbon mounted on a linear actuator. The infrared emission spectra from Fe, Cu, Zn, and Al atoms were observed in the 2.5-5 µm region with a time profile showing maximum emission intensity in 3-5 µsec after a laser shot. The time profile was explained by diffusion process. The observed emission spectrum from iron ablation in the 2500 cm^-1 region agrees very well with solar absorption spectrum, where new lines have been detected in the present experiment in addition to the lines observed from a hollow cathode discharge. When O₂ was added to the carbon ablation, emissions from vibrationally excited CO was observed with a vibrational temperature of 12300~K. Based on the observed time profiles, relaxation processes will be discussed.