1. Time-resolved Fourier transform infrared emission spectroscopy of
laser ablation products
K. Kawaguchi1, N. Sanechika1, Y. Nishimura1,
R. Fujimori1, T. N. Oka2, Y. Hirahara2, A. I. Jaman3, and
S. Civis4
Okayama University1
Nagoya Univversity2
Saha Institute3
Heyrovsky Institute4

2. Laser ablation - spectroscopy
LIF : metal compounds: YO, YF (1993)
FT MW: metal compounds: YO, LaO, ZrO, HfO biomolecules: amino acids
Infrared : diode laser : C5, C7, C9
many matrix isolation studies
grating : YO emission
Recently high repetition rate laser (1-10 kHz)
Application to TR-FTS (1) atomic spectra
(2) reaction product of C and O2

3. Block diagram of TRFTS system
Laser trigger
Nd:YLF laser
Laser ablation
ADC 4322
16 bit
≲ 2 MHz
New method
SX is replaced by FPGA
(Field Programmable Gate Array)

4. Timing diagram for TRFTS
Scan siganal
200 msec
He-Ne laser
2nd scan
1st scan
Trigger for Pulse laser
sampling
64 spectra
64 interferograms
½ sampling : sampling 5 kHz, pulse laser 2.5 kHz

5. Laser ablation Nd:YLF laser 527 nm 1.6 mJ/pulse 2.5 kHz Motor To FTS
5 rot/sec
To FTS
lens
Metal rod
Actuator

6. Emission spectrum from laser ablation of Fe
2742:g7D-
s6D6p7Do
2743:g7D-
s6D6p7Fo
2781: 4f-5g
2778: 5d-5f
2662: 5p-6s
(Nave et al.
1994)
cm-1
Total 137 lines
67 un-identified

7. Emission spectrum of Fe I
Absorption
Spectrum of Sun
(ATMOS)
Emission from iron ablation
Nave et al.
APJS 94, 221(1994)
Hollow cathode
Fe I 3d 64s(6D)4f – 3d 64s(6D)5g
61800 cm-1 high

8. Emission spectrum from ablation of iron
SUN
absorption a b
Emission
from iron
ablation
a:5d-5f
b:v 5P0-e 3P
New line

9. Ablation from brass
Cu : U
Cu 6s-6p

10. Time profiles of ablated Fe and Cu

11. Time profile of Cu line (2497.8 cm-1)

12. Diffusion process Boltzmann equation
Imajyo, Higuchi, Yamakita, Bunko Kenkyu, 55,394(’06)
Collision cross
section
A:0.25 s
B:0.4 “
C:0.6 “
D:0.8 “
E:1.0 “
s=4.16x10-19 m2

13. CO emission C(gas) + O2 -> CO + O -578 kJ/mol (48258 cm-1)
v=1-0
O2 =500 mTorr
C(gas) + O2 -> CO + O kJ/mol
(48258 cm-1)
Up to v=13-12, Eu=26000 cm-1
limited by InSb detector

14. Rotational distribution in v=6
Error:30K

15. Vibrational distribution
CO (v)
+ CO (v=0)
⇆ CO (v-1)
+ CO(v=1)
Vib. relax
slow
10-12 cm3s-1
5 mTorr CO
5.8 msec　
non-equilibrium

16. Vibrational relaxation
v=6-5 P(8)
160 mTorr CO
t=180 msec

17. Summary laser ablation products monitored by TR-FTS
(1) High energy states of Fe I related to solar
absorption spectrum : comparison with
discharge
(2) Diffusion process : collisional cross
section
(3) Reaction of O2 and carbon
non-equilibrium vibrational distribution