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

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

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 3.01605g 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

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.

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

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

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

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

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

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

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)

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

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

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）

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 = 0.047 cm-1

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

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

Acknowledgment Hiroki Maki and Takuya Yamamoto Masanori Hara Funding Kakenhi (Grant No. 18760635, 20049002, 24561022) Joint research program of Hydrogen Isotope Research Center n