Einstein A coefficients and Oscillator Strengths for the

  • Slides: 22
Download presentation
Einstein A coefficients and Oscillator Strengths for the A 2 П-X 2Σ+ (red) and

Einstein A coefficients and Oscillator Strengths for the A 2 П-X 2Σ+ (red) and B 2Σ+-X 2Σ+ (violet) Systems of CN R. S. RAM, J. S. A. BROOKE Department of Chemistry, University of York, Heslington, York YO 10 5 DD, UK. G. LI Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA D. W. SCHWENKE NASA Ames Research Center, Moffett Field, CA 94035 -10000, USA and P. F. BERNATH 2 Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529 USA

OUTLINE

OUTLINE

Introduction

Introduction

Interstellar CN Violet 0 -0 Diffuse interstellar cloud absorption towards the star HD 169454

Interstellar CN Violet 0 -0 Diffuse interstellar cloud absorption towards the star HD 169454 Gredel et al. AA, 251, 625 (1991) [12 CN]/[13 CN]=38 See also, A. Mc. Kellar, PASP, 52, 187 (1940) Trot = 3 K (same temperature as the cosmic background radiation)

CN (3, 0) (red) in translucent clouds Early-type stars Schmidt et al. MNRAS 431,

CN (3, 0) (red) in translucent clouds Early-type stars Schmidt et al. MNRAS 431, 1795 (2013) WGB stars Adamczak & Lambert Ap. J 765, 155 (2013)

Summary of Spectroscopic Studies A 2 П-X 2Σ+ (red system) 12 C 14 N:

Summary of Spectroscopic Studies A 2 П-X 2Σ+ (red system) 12 C 14 N: Ram et al. , JMS 263, 82 (2010) 13 C 14 N: Ram et al. , Ap. J Suppl. Ser. 188, 500 (2010); JMS 274, 22 (2012) More than 60 bands with v´=0 -22, v˝=0 -12, were analyzed for both isotopologues [4000 -22000 cm-1] B 2Σ+ -X 2Σ+ (violet system) 12 C 14 N: Ram et al. , JMS 237, 22 (2006) 13 C 14 N: Ram et al. , Ap. J Suppl. Ser. 194, 34 (2011) More than 50 bands with v´=0 -15, v˝=0 -15 were analyzed [20000 -29000 cm-1] 12 C 15 N: Colin & Bernath, JMS 273, 30 (2012)

Lifetimes of the A 2Π state Lu, Huang, Halpern, Ap. J 395, 710 (1992)

Lifetimes of the A 2Π state Lu, Huang, Halpern, Ap. J 395, 710 (1992)

Method of Calculation

Method of Calculation

Comparison of the A 2Π state lifetimes (in μs)

Comparison of the A 2Π state lifetimes (in μs)

Comparison of the B 2Σ+ state lifetimes (in ns)

Comparison of the B 2Σ+ state lifetimes (in ns)

Calculation of Av'v" and fv'v" values of the A 2 П-X 2Σ+ transition of

Calculation of Av'v" and fv'v" values of the A 2 П-X 2Σ+ transition of CP A 2 П-X 2Σ+ Measurements B-X Herzberg (1930) B-A Bärwald et al. (1934) IRC+10216 Guélin et al. (1990) Cernicharo et al. (2000) Tenenbaum et al. (2007) Ram & Bernath, JMS 122, 282 (1987) Ram & Bernath, JMS 152, 89 (1992) Microwave and THz measurements Saito et al. Ap. J 341, 1114 (1989) Klein et al. Z. Naturforsch 54 a, 187 (1999) Transition dipole moments Brouckère & Feller, J. Phys. B 31, 5053 (1998) Intensity calculations for 75, A-X bands with v=0 -8 levels of both states

CONCLUSION

CONCLUSION

ACKNOWLEDGMENTS LEVERHULME TRUST NASA LABORATORY ASTROPHYSICS PROGRAM NATIONAL SOLAR OBSERVATORY End Thank you for

ACKNOWLEDGMENTS LEVERHULME TRUST NASA LABORATORY ASTROPHYSICS PROGRAM NATIONAL SOLAR OBSERVATORY End Thank you for your attention !

Star Classification Astronomers classify stars by color using a series of letters: O, B,

Star Classification Astronomers classify stars by color using a series of letters: O, B, A, F, G, K and M. Under this classification, O stars are the hottest, and M stars are the coolest, with the other letters coming in between. O stars are “blue”, A stars are “white”, G stars are “yellow”, and M stars are red.