1. THE ANALYSIS OF 2ν3 BAND OF HTO
Kaori Kobayashi1, Hiroki Maki1, Takuya Yamamoto1, Masanori Hara2, Yuji Hatano2, Hiroyuki Ozeki2
1. Department of Physics, University of Toyama
2. Hydrogen Isotope Research Center, University of Toyama
3. Department of Environmental Science, Toho University
Jun 16th 2014
69th International Symposium on Molecular Spectroscopy 1

2. Outline
Motivation
Improvement of the experimental system and new measurement
Analysis of the near-infrared spectra of HTO
Future plan
Acknowledgment

3. Motivation
Spectroscopic studies of water has a long history and are still attractive.
Tritium, hydrogen-3
Symbol
3H、T
Life time
12.3 years
Atomic mass g
Nuclear equation
T → 3He + e－ + νe
Decay
b-decay　18.6keV
Near-infrared spectroscopy is suitable for two reasons.
・stable windows are available for a safe experiment.
・multi isotopologue detection is possible.
No data for tritiated water（HTO,T2O)in the near-infrared region

4. Tritium
Tritium is used in the experimental fusion reactor ITER built in France.
Monitoring tritium is indispensible.
The concentration could be differ by 12 orders of magnitude and spectroscopy can serve as one of the monitoring methods.
Spectroscopy can also provide information on chemical species of tritium.

5. Tritiated water
Hydrogen gas isotopologues are analyzed by Raman spectroscopy
Water is one of the most important chemical species
Tritiated water or partially tritiated water is said to affects human body 10,000 times more than tritium gas.
It is considered that released tritium is turned into tritiated water quickly.
Application of near-infrared spectroscopy

6. Vibrational modes of water
（n1, n2, n3 ）
symmetric stretching bending anti-symmetric stretching
O-D, O-T bending O-H stretching n1 n3 n2 n1 n2 n3
H2O
3657 cm⁻1
1595 cm⁻1
3756 cm⁻1
HTO
2300 cm⁻1
1333 cm⁻1
3717 cm⁻1
T2O
2234 cm⁻1
995 cm⁻1
2367 cm⁻1

7. Vibrational energy level of water and tritiated water（HTO and T2O）
cm-1
H2O
HTO
T2O
8000
(002)
(002)
(150)
(101)
(220)
7000
(102)
(201)
(101)
6000
(011)
Estimated based on Tennyson’s group
(011)
5000

8. Previous High-Resolution Spectroscopic Studies of Tritiated Water
HTO
　P. Helminger et al. Phys. Rev. A 10, 1072(1974)　 MW
　S. D. Cope et al. J. Mol. Spectrosc. 127, 464 (1988)　mid-IR
　P. P. Cherrier et al. J. Mol. Spectrosc. 121, 69 (1987) 　mid-IR
　Tine et al. J. Mol. Phys. 3, 1945 (2012) 　mid-IR
T2O
　F. De Lucia et al. Phys. Rev. A 8, 2785(1973) 　MW
S. D. Cope et al. J. Mol. Spectrosc. 120, 311 (1986) 　mid-IR
H. A. Fry et al. J. Mol. Spectrosc. 103, 41 (1984) 　mid-IR
Lack of tritium spectroscopic information
in the near infrared region

9. 3 years ago… in Columbus Preliminary experimental results
Limited frequency range and lack of the information on composition made the assignments difficult
Started to get help from ab initio calculations thanks to Tennyson’s group

10. Problem Associated with Our Single Wall Cell
b -decay
3He e-
b –ray induced decomposition
Laser
　b –decay of tritium
T → 3He + e－ + νe
　The behavior of the remnant gas was different from 3He
　　⇒　 Indicating the back reaction to T2
Liq.N

11. The Preparation of the Double-Wall Cell and Synthesis of Tritiated Water
Inner tub φ10.5mm×1025mm View Port : ICF34 (quartz) Outer tube φ35mm×1050.4mm View Port : ICF70 (pyrex) ・Leak test was well-done T2 3.7x1010 Bq (cas. 0.7 mg)

12. Experimental setup for spectroscopy
Laser
EOM
Wavemeter
Sample Cell
Baratron　Gauge
Ion Pump
Water Reservoir
IR Detector
Amplifier
Mixer
Signal Generator
Controller PC
Optical Alignment Cablelines Vacuum connections

13. Spectrum N2 12℃ humidity 30-35％FM
direct absorption

14. Assignment About 100 cm-1 with gaps was scanned so far
Assignment was based on a quantum chemical calculations
(Down et al, J. Mol. Spectrosc., 289, 35 (2013))
(002) 77 lines　（6）
(111) 17 lines　（1）
(220) 6 lines　 （5）

15. Analysis of the (002) level
Watson’s A-reduced Hamiltonian was used.
Ground state parameters are fixed to those determined by microwave spectroscopy
Only excited state parameters were float.
Transitions with obs.-calc.>0.1 cm-1 were omitted.
63 transitions out of 77 were used in the fit.
　rms = cm-1

16. Perturbation Rms=0.047 cm-1>>Experimental errors ca. 0.005 cm-1
Possibility of perturbation
Likely perturbing states
(111) and（220）
HTO
ν１+ν2≈ν3
cm-1
(002) 7236
HTO
7100
7200
7300
7400
(111) 7336
(220) 7102

17. Summary and Future Work
Analysis of the experimental data of 2n3 band
New double-walled cell system was prepared
Future
Perturbation analysis of HTO
T2O spectroscopy in the longer wavelength region
Clarification of tritiated water chemistry

18. Acknowledgment Hiroki Maki and Takuya Yamamoto Masanori Hara Funding
Kakenhi (Grant No , , )
Joint research program of Hydrogen Isotope Research Center n