1. Fumie X. Sunahori, Jie Wei, and Dennis J. Clouthier Department of Chemistry, University of Kentucky

2. HCP + ?? Previously…

3. HCP + CCP !! v ' =0 Discovery

4. Why Study CCP?  No previous work  Only 8 of 44 possible dicarbides have been discovered (C 2 X, X = H, B, C, N, O, Si, S, Cl)  Structure (Linear? Cyclic?)  Astrophysical Significance

5. Experimental Gas Mixture: CH 4 + PCl 3 in Ar

6. HCP + CCP Are We Sure? ??

7. 88 66 77 22 33 X 2  r  99 (1) 2  Excited state (2) 2  - Excited state (3) 2  + Excited state Background

8. [core] 6  2 7  2 8  2 2  4 9  2 3  1  X 2  r Split the ground state into two spin-components A  2  1/2 2  3/2 E Excited State If It Is CCP…

9. A = 140.8 cm -1 HCP + |A|= 146.97 cm -1 Low-Resolution LIF Spectrum

10. 1.Rotational Constant B"(CCP) = 0.21247 cm -1 [exp. B" = 0.21314 cm -1 ] B"(CPC) = 0.24624 cm -1 2.Spin-Orbit Coupling Constant Small A is expected for CPC cf. A"(CCN) = 40.34 cm -1  A"(CNC) = 26.41 cm -1 3.Stability CPC is predicted to lie much higher (88.0 kcal) a in energy compared to the ground state CCP 4.Number of isotopomers 3 isotopomers for CPC; 4 isotopomers for CCP a CCSD(T)/cc-pVTZ calculation; J. El-Yazal et al. J. Phys. Chem. A. 101, 8319(1997). Can It be CPC?

11. Exp. 1 = 1644 cm -1 3 = 833 cm -1 A = 142 cm -1 Exp. 1 = 1594 cm -1 3 = 813 cm -1 A = 145 cm -1 A A Vibrational Structure Ab initio 1 = 1726 cm -1 3 = 847 cm -1 Ab initio 1 = 1659 cm -1 3 = 829 cm -1

12. 1 = 1644 cm -1 3 = 833 cm -1 A = 142 cm -1 Exp. 1 = 1692 cm -1 3 = 661 cm -1 A = 874 cm -1 Discovery of CCAs Ab initio 1 = 1749 cm -1 3 = 675 cm -1

13. 1 1010 12 CH 4 + PCl 3 13 CH 4 + PCl 3 33.7 cm -1 [37.8 cm -1 ] 41.0 cm -1 [41.8 cm -1 ] 75.5 cm -1 [81.2 cm -1 ] Isotope Shifts 12 CH 4 + 13 CH 4 + PCl 3

14. Rotational Analysis A' -0.107 cm -1

15. Spin-Orbit Coupling Constant A X 2rX 2r ~ A 2iA 2i ~ A" +140.5 cm -1 A' -0.107 cm -1 A' (CCN) -0.8 cm -1 A" (CCN) +40.34 cm -1 R 11 (1.5) R 21 (1.5) 22 22    

16. [1.3144 Å] 1 1.597 Å [1.6203 Å] 1 1.673 Å 1: CCSD(T) calculations 1.54020 Å 1.20241 Å1.3391 Å 1.597 Å [1.6203 Å] 1 Structure of CCP (X 2  ) ~

17. 1.673 Å 1: B3LYP calculations 1.20241 Å1.3391 Å [1.2334 Å] 1 1.692 Å [1.698 Å] 1 Structure of CCP (A 2  ) ~

18. Effective Hamiltonian: H = H vib + H SO + H RT + H a + H FR  = 0.594  2 = 305.3 cm -1 A  = 162.2 cm -1 Renner-Teller Analysis (X 2  ) ~

19. Renner-Teller Analysis (A 2  ) Effective Hamiltonian a H = H vib + H RT + H a + H SO ~   24g 4 ^ 4g K a J. M. Brown & F. Jørgensen, Mol. Phys. 47, 1065 (1982).

20. CCP in Space FD07 “Detection of the CCP Free Radical in IRC+10216” D. T. Halfen, D. J. Clouthier, and L. M. Ziurys http://aro.as.arizona.edu/

21. Thank you! 有難うございました。 謝謝！ Merci! Danke! Grazie! Gracias! Spasibo! Dziekuje! …

22. Renner-Teller Anaysis (A 2  ) (Energy Formulae) For Unique Levels (|K|  v 2 ): For Non-Unique Levels (|K| < v 2 ): where

23. Constants X 2  A 2A 2 B"B"0.213 137 7 (52)B'B'0.207 549(51) A"A"140.503 7(42)A'A'-0.107 4(36) 10 4 A D "7.43 3 (31)T0T0 15 898.819 4 3 (21)

24. 12 C 2 P 13 C 2 P 11 1 646.36(58)1 609.6 5 (27) 22 211.34 7 (91)204.01(96) 33 837.75(44)819.0(15) gKgK -4.4 6 (11)-2.9 1 (13)  0.594 3(62)0.584 8(61) A162.2 5 (10)161.7 6 (10) Renner-Teller Analysis (X 2  ) ~

25. Renner-Teller Analysis (A 2  ) ~ 12 C 2 P 13 C 2 P 11 1 824.3 7 (15)1 752.85(78) 22 305.2 6 (14)294.58(29) 33 731.4 7 (17)714.13(64) gKgK 1.62(31)1.44 3 (11) g 22 1.9(4)1.67 8 (10) g4g4 0.62(5)0.566(24) ^

26. 1 =1 2 =1 1 =-1 2 =-1  = 2  = -2  1 =-1 2 =1 1 =1 2 =-1  = 0  2+2+4-4- 22 2-2-