1. Laser spectroscopic study of CaH in the B 2 Σ + and D 2 Σ + state Kyohei Watanabe, Kanako Uchida, Kaori Kobayashi, Fusakazu Matsushima, Yoshiki Moriwaki Department of Physics, University of Toyama

2. Back ground(1) ・ The electronic transitions of CaH have been found in the Sun and M type dwarf stars, and can be used to study them. ・ It is suggested that the B 2 Σ + has an interesting double minimum potential due to avoid crossing, which is also called as B/B' 2 Σ +. CaH is interesting in the astronomical and spectroscopic points of view P.F.Weck,P.C.Stancil,K.Kirby J.Chem.Phys. 118, 9997(2003) Potential energy curves of CaH calculated by P. F. Weck et al.

3. We have carried out laser spectroscopic study of CaH in the UV region. Spectroscopic studies on CaH began in the 1920’s, and many studies have been carried out since then. P. F. Bernath et al. X 2 ∑ + v'=1,0 v''=3,4[1] E 2 Π － X 2 ∑ + ⊿ v=0 v'=0,1[2] E 2 Π － X 2 ∑ + v'=0,1 v''=0, 1, 2, 3, 4[3] A 2 Π － X 2 ∑ + ⊿ v=0,-1 v'=1,2,3 B 2 ∑ + － X 2 ∑ + ⊿ v=0 v'=1,2,3 [4] G.D.Bell et al.Physica Scripta 20, 609(1979) D 2 ∑ + － X 2 ∑ + v'=4~12 v''=0, v'=12 v''=1 Back ground(2) history P.F.Weck,P.C.Stancil,K.Kirby J.Chem.Phys. 118, 9997(2003) Potential energy curves of CaH calculated by P. F. Weck et al. [1]A. Shayesteh, et al., Mol. Struct. 695-696, 23(2004) [2]R. S. Ram, et al., J. Mol. Spectrosc. 266, 86(2011) [3]G. Li, et al., J. Quant. Spectro. Rad. Transfer 113, 67(2012) [4]A. Shayesteh, et al., J. Mol. Struct. 288, 46(2013) Birger Grundstrom Z. Phys. 75, 302( 1932) D2∑+－X2∑+D2∑+－X2∑+

4. Experimental setup Experimental methodology: Laser induced fluorescence. Production a CaH: Laser ablation of a calcium target in a hydorogen gas. Excitation laser ： SHG of dye laser pulse (360nm ~ 430nm). Detection of LIF: detecting the fluorescence from CaH by a PMT through a monochromator. time sequence of laser pulses YAG pulsedye pulse t 40μs pulsed Nd:YAG laser calcium sample monochromator (f=250mm) vacuum chamber H 2 gas to PMT Pulsed SHG of dye laser

5. Result [5,6] [5]G. D. Bell et al. Physica Scripta, 20, 609(1979). [6]Birger Grundstr ö m Z. Phys. 75, 302( 1932) Excitation spectrum LIF@678nm(14750cm -1 ) Pressure of H 2 gas: 2Torr #1# 3 #4 # 2

6. J''→J'symObs. /cm -1 Calc. /cm -1 Obs. － Calc. 1.5→2.5f24904.8324904.93-0.10 2.5→3.5f24901.4724901.49-0.02 2.5→1.5f24863.2624863.110.15 3.5→2.5f24845.8224845.84-0.02 2.5→3.5e24903.2624903.200.06 3.5→4.5e24899.2424899.26-0.02 3.5→2.5e24862.0324861.800.23 4.5→3.5e24844.0424844.020.02 34 line are assigned #2#2 Assignment(1) J''→J'symObs. /cm -1 Calc. /cm -1 Obs. － Calc. 4.5→5.5f23890.6023890.430.17 5.5→6.5f23878.6923878.70-0.01 6.5→5.5f23781.0623780.940.12 7.5→6.5f23752.4123752.51-0.10 3.5→4.5e23902.8223902.730.09 4.5→5.5e23896.3823896.44-0.05 5.5→4.5e23826.9223826.710.20 6.5→5.5e23803.2823803.61-0.34 25 line are assigned #1#1

7. J''→J'symObs. /cm -1 Calc. /cm -1 Obs. － Calc. 1.5→2.5f24301.7424302.04-0.30 2.5→3.5f24294.8524295.18-0.33 1.5→0.5f24278.8324279.06-0.23 2.5→1.5f24262.6024262.91-0.31 0.5→1.5e24304.6824304.170.51 1.5→2.5e24304.6824304.75-0.07 2.5→1.5e24278.8324278.760.07 3.5→2.5e24262.6024262.440.16 46 line are assigned Assignment(2) J''→J'symObs. /cm -1 Calc. /cm -1 Obs. － Calc. 2.5→3.5f25857.5125857.61-0.10 3.5→4.5f25849.9725850.11-0.14 7.5→6.5f25699.1925699.20-0.01 8.5→7.5f25665.2725665.260.01 4.5→5.5e25847.4225847.44-0.03 5.5→6.5e25836.1725836.26-0.09 5.5→4.5e25779.6725779.390.28 6.5→5.5e25754.6925754.620.07 41 line are assigned #4 #3

8. Molecular constants Hamiltonian: * A. Shayesteh, et al, J. Mol. Struct. 695-696, 23 (2004). X 2 Σ + v=0* fixed#1#1#2#2#3#3#4#4 T0 23898.71(13)24896.73(06)25852.83(29) 24299.72(04) B4.2287 2.7954(38)2.7161(24)2.6924(65) 2.2733(16) D1.85074×10 -4 4.03(25) ×10 -4 2.40(20)7.86(30) ×10 -4 -8.85(10)×10 -4 γ4.36×10 -2 -0.508(19)-0.482(14)-0.515(43) 0.063(13) γDγD -5.1×10 -6 5.59(22) ×10 -4 3.10(18) ×10 -4 11.12(34) ×10 -4 -18.8(12)×10 -4

9. Rotational temperature #4 band

10. ・ There’s no Q-branch in #1, #2, #3 and #4 band, which suggests these transitions are Σ-Σ. Discussion(1): electric state assignment ・ #1, #2, #3 and #4 shell be assigned to D 2 ∑ + -X 2 ∑ + or B/B’ 2 ∑ + -X 2 ∑ + considering our measured frequency range.

11. ・ the upper states of #1, #2, and #3 bands have similar γ values, whereas that of #4 has a value much different from those of #1,#2 and #3. D 2 ∑ + ν [1,2] T0T0 Bγ 022521.47(87)2.626(18)-0.025(92) 223606.14(26)2.5565(53)0.049(27) 424627.38(22)2.491(18)-0.070(28) 525273.45(09)2.1791(39) 0.064(18) 625592.19(18)2.4102(44)-0.034(29) 726199.22(07)2.0924(28) 0.239(14) 826504.52(20)2.2922(48) 0.111(32) 927064.72(33)2.031(20) 0.045(80) 1027352.47(17)2.0846(48) 0.123(30) 1228106.62(08)1.7838(30) 0.106(14) [1] Calculate from G.D.Bell et al.Physica Scripta 20, 609(1979) [2] Calculate from Birger Grundstr ö m Z. Phys. 75, 302( 1932) BandT0T0 Bγ #123898.71(13) 2.7954(38) -0.508(19) #2 24896.73(06)2.7161(24) -0.482(14) #3 25852.83(29)2.6924(65) -0.515(43) #4 24299.72(04)2.2733(16) 0.063(13) Discussion(2) ・ #4 has a γ value similar to that of D 2 ∑ +, so we assigned #4 to D 2 ∑ + -X 2 ∑ + and #1,#2 and #3 assigned to B/B’ 2 ∑ + -X 2 ∑ +. Consideration from gamma value

12. Discussion(3) T and B of D 2 ∑ + ν=3 There are two series in D 2 ∑ + for even and odd number v Consideration from T and B

13. Problem(1) Value of D is minus for band #4 perturbation effect? X 2 Σ + v=0[4] fixed#1#1#2#2#3#3#4#4 T0 23898.71(13)24896.73(06)25852.83(029) 24299.72(04) B4.2287 2.7954(38)2.7161(24)2.6924(65) 2.2733(16) D1.85074×10 -4 4.03(25) ×10 -4 2.40(20)7.86(30) ×10 -4 -8.85(10)×10 -4 γ0.0436 -0.508(19)-0.482(14)-0.515(43) 0.063(13) γDγD -5.1×10 -6 5.59(22) ×10 -4 3.10(18) ×10 -4 11.12(34) ×10 -4 -18.8(12)×10 -4

14. Missing intensity in low J transitions of #3 bands Band #3 Problem(2)

15. Band #1 Band #2 Band #3 Problem(2) Band #4 Calc.(300K) Line intensity of the J transitions of #1 and #2 bands also truncated

16. [7]T. Leininger and Gwang-Hi Jeung J. Chem. Phys. 103, 3942 (1995). [8]Shayesteh et al. J. Mol. Struct. 288, 46(2013). [9]G. D. Bell et al. Physica Scripta, 20, 609(1979). [10] Birger Grundstrom Z. Phys. 75, 302( 1932) internuclear distance (bond length) calculated from B constants R /bohr E /cm -1 × ： theoretical value calculated from potential energy [7] ★： our work ● ： experimental value [8,9,10] Problem(3) D2∑+D2∑+ B/B’ 2 ∑ +

17. R /bohr E /cm -1 [7]T. Leininger and Gwang-Hi Jeung J. Chem. Phys. 103, 3942 (1995). [8]Shayesteh et al. J. Mol. Struct. 288, 46(2013). [9]G. D. Bell et al. Physica Scripta, 20, 609(1979). [10] Birger Grundstrom Z. Phys. 75, 302( 1932) internuclear distance (bond length) calculated from B constants Problem(3) × ： theoretical value calculated from potential energy [7] ★： our work ● ： experimental value [8,9,10]

18. Conclusion ・ We observed new bands of CaH and assigned rotational transitions for 4 bands. ・ We confirmed that the lower state of these bands is the ground state X 2 Σ +, v=0 of CaH. ・ The upper states are tentatively assigned to the B/B’ 2 Σ + state and D 2 Σ + state. ・ assignment of the other observed bands. ・ ab initio calculation up-to-date Future plan

19. relative intensity Obs./Calc. Band #1 Band #2 Band #3 Band #4