1. EXPERIMENTAL TRANSMISSION SPECTRA OF HOT AMMONIA IN THE INFRARED Monday, June 22 nd 2015 ISMS 70 th Meeting Champaign, Illinois EXPERIMENTAL TRANSMISSION SPECTRA OF HOT AMMONIA IN THE INFRARED Monday, June 22 nd 2015 ISMS 70 th Meeting Champaign, Illinois

2. EXPERIMENTAL TRANSMISSION SPECTRA OF HOT AMMONIA IN THE INFRARED Monday, June 22 nd 2015 ISMS 70 th Meeting Champaign, Illinois INTRODUCTION Ammonia has been found in a number of astronomical objects Jupiter: In the visible (Wildt, 1931) At 10 μm (Gillett et al., 1969) Also by spacecraft (Voyager, Cassini, Galileo) Brown dwarfs: At 10 μm (Cushing et al., 2006) Interstellar clouds: Rotational and inversion (Ho & Townes, 1983) Exoplanets: Predicted from models (Line et al., 2011)

3. EXPERIMENTAL TRANSMISSION SPECTRA OF HOT AMMONIA IN THE INFRARED Monday, June 22 nd 2015 ISMS 70 th Meeting Champaign, Illinois AMMONIA (NH 3 ) ModeSymmetryFrequency (cm -1 )Type ν1ν1 a1a1 3336.2 (3337.2)Symmetric Stretch ν2ν2 a1a1 932.5 (968.3)Symmetric Bend ν3ν3 e3445.6 (3443.9)Anti-symmetric Stretch ν4ν4 e1626.1 (1627.4)Anti-Symmetric Bend Fundamental modes of ammonia Rotational Constants B 0 9.9443 cm -1 C 0 6.196 cm -1 r 0 1.0171 Å α 107.8°

4. EXPERIMENTAL TRANSMISSION SPECTRA OF HOT AMMONIA IN THE INFRARED Monday, June 22 nd 2015 ISMS 70 th Meeting Champaign, Illinois NH 3 in brown dwarfs AMMONIA IN ASTRONOMY T dwarfs; 500-1300 K Cushing et al., 2006 Cushing et al., 2011 Mid-late T & Y0 dwarfs; 400-1100 K

5. EXPERIMENTAL TRANSMISSION SPECTRA OF HOT AMMONIA IN THE INFRARED Monday, June 22 nd 2015 ISMS 70 th Meeting Champaign, Illinois AMMONIA IN ASTRONOMY Hot Jupiter, 1500 K Burrows, 2014 NH 3 in exoplanets Strong NH 3 absorption

6. EXPERIMENTAL TRANSMISSION SPECTRA OF HOT AMMONIA IN THE INFRARED Monday, June 22 nd 2015 ISMS 70 th Meeting Champaign, Illinois SPECTROSCOPIC REQUIREMENTS

7. EXPERIMENTAL TRANSMISSION SPECTRA OF HOT AMMONIA IN THE INFRARED Monday, June 22 nd 2015 ISMS 70 th Meeting Champaign, Illinois UTILITY OF HOT LAB SPECTRA Why do we need hot lab spectra? HITRAN 1 (Rothman et al., 2012) is a widely used spectroscopic database but was designed for use with the Earth’s atmosphere which presents two main problems; Lack of hot bands Broadening parameters are based on air ab initio calculations such as ExoMol 2 provide a large number of lines but the accuracy in line positions have limited reliability. For the most complete line list at high temperature a combination of experimental and theoretical calculations are required. 1 HITRAN sources for NH 3 ; 2150-3100 cm -1 (Kleiner et al. 1995) 2200-2750 cm -1 (Cottaz et al. 2001) 2980-3635 cm -1 (Kleiner et al. 1999) 4030-4710 cm -1 (Urban et al. 1989) 4790-5295 cm -1 (Brown & Margolis 1996) 2 Specifically BYTe database for NH 3 (Yurchenko et al. 2011)

8. EXPERIMENTAL TRANSMISSION SPECTRA OF HOT AMMONIA IN THE INFRARED Monday, June 22 nd 2015 ISMS 70 th Meeting Champaign, Illinois Our group has created line lists for NH 3 at high temperatures in the mid-IR. PREVIOUS WORK These spectra were recorded in emission which results in problems with self absorption At higher wavenumbers emission becomes weaker

9. EXPERIMENTAL TRANSMISSION SPECTRA OF HOT AMMONIA IN THE INFRARED Monday, June 22 nd 2015 ISMS 70 th Meeting Champaign, Illinois Spectral range: 2400-5500 cm -1 at 0.02 cm -1 resolution Cell pressure: 40 Torr Temperatures recorded: 22°C, 200°C, 300°C, 400°C, 500°C, 600°C, 700°C Signal dramatically decreased above 700°C due to thermal decomposition NEW CELL DESIGN + EXPERIMENTAL New cell design Quartz halogen Lamp Furnace Heating elements Quartz sample tube 75 cm To FTS Outer supporting tube Inner draught tube Zirconia draught spacers Profile from the side:

10. EXPERIMENTAL TRANSMISSION SPECTRA OF HOT AMMONIA IN THE INFRARED Monday, June 22 nd 2015 ISMS 70 th Meeting Champaign, Illinois LOWER STATE ENERGIES

11. EXPERIMENTAL TRANSMISSION SPECTRA OF HOT AMMONIA IN THE INFRARED Monday, June 22 nd 2015 ISMS 70 th Meeting Champaign, Illinois LOWER STATE ENERGIES 4ν2-ν2/ν1-ν2/ν3-ν24ν2-ν2/ν1-ν2/ν3-ν2 ν 1 /ν 3 /2ν 4 ν1+ν2/ν2+ν3ν1+ν2/ν2+ν3 ν1+ν4/ν3+ν4ν1+ν4/ν3+ν4 3ν2/ν2+ν43ν2/ν2+ν4

12. EXPERIMENTAL TRANSMISSION SPECTRA OF HOT AMMONIA IN THE INFRARED Monday, June 22 nd 2015 ISMS 70 th Meeting Champaign, Illinois COMPARISON TO THEORY 296 K

13. EXPERIMENTAL TRANSMISSION SPECTRA OF HOT AMMONIA IN THE INFRARED Monday, June 22 nd 2015 ISMS 70 th Meeting Champaign, Illinois COMPARISON TO THEORY 773 K

14. EXPERIMENTAL TRANSMISSION SPECTRA OF HOT AMMONIA IN THE INFRARED Monday, June 22 nd 2015 ISMS 70 th Meeting Champaign, Illinois COMPARISON TO THEORY 296 K

15. EXPERIMENTAL TRANSMISSION SPECTRA OF HOT AMMONIA IN THE INFRARED Monday, June 22 nd 2015 ISMS 70 th Meeting Champaign, Illinois COMPARISON TO THEORY 773 K

16. EXPERIMENTAL TRANSMISSION SPECTRA OF HOT AMMONIA IN THE INFRARED Monday, June 22 nd 2015 ISMS 70 th Meeting Champaign, Illinois High resolution data is essential for modeling astronomical atmospheres. Extrapolation of room temperature data is insufficient due to absence of hot lines. Theoretical results do not accurately determine line positions needed for modeling. Experimental spectra are therefore needed at applicable temperatures, these have been acquired in an appropriate spectral region in transmission. These data can be used to improve theoretical predictions of astronomical spectra. SUMMARY

17. EXPERIMENTAL TRANSMISSION SPECTRA OF HOT AMMONIA IN THE INFRARED Monday, June 22 nd 2015 ISMS 70 th Meeting Champaign, Illinois FUTURE WORK Record transmission spectra of NH 3 and CH 4 further towards near infrared Extend line lists with E low Use accurate line positions to help constrain theoretical methods ACKNOWLEDGEMENTS Bernath group at ODU NASA for funding FUTURE WORK + THANKS