Nuclear Spin Dependence of the Reaction of H3+ with H2 Kyle N. Crabtree, Lt. Col. Brian A. Tom, USAF, Carrie A. Kauffman, and Benjamin J. McCall University of Illinois 23 June 2010 http://bjm.scs.uiuc.edu

Nuclear Spin Effects in Dense Hydrogenic Plasmas Kyle N. Crabtree, Lt. Col. Brian A. Tom, USAF, Carrie A. Kauffman, and Benjamin J. McCall University of Illinois 23 June 2010 http://bjm.scs.uiuc.edu

+ H H3+: Why is it important? Dominant ionic species in hydrogenic plasma Cornerstone of interstellar gas-phase ion-molecule chemistry

Astronomical Spectroscopy of H3+ 36685 Å R(1,1)u 36681 Å B. J. McCall Ph.D. Thesis, University of Chicago (2001).

Temperature Discrepancy Temperature derived from H3+ in diffuse clouds ≠ cloud kinetic temperature T (H3+) ~ 30 K T (kinetic) ~ 70 K H3+ + H2  H2 + H3+ reaction allows H3+ population to transfer between ortho and para spin configurations

Para-H2 Production 15 K >99.9% purity Ferric Oxide catalyst B. A. Tom, S. Bhasker, Y. Miyamoto, T. Momose, and B. J. McCall Rev. Sci. Inst (2009), 80, 016108

Hollow Cathode Cell T = 110 – 350 K

Spectrometer Spectral Range: 2.2-4.8 μm Output Power: 500-700 μW V HV 200 ms GND time InSb

Observed Transitions R(3,0) R(3,3)l R(2,1)u R(2,2)l R(1,0) R(1,1)u

Normal H2, No Cooling Pulse Shape: R(1,0) Pulse on Pulse off Tkin Abs. Frequency

Normal H2, No Cooling Temperatures

Normal H2, No Cooling Para-H3+ Percentage t = 300 ms

Normal H2, No Cooling Rotational Temperature Trot ~ 350 K

No Cooling, Enriched p-H2 Peak Areas ortho-H3+ para-H3+ para-H3+

No Cooling, Enriched p-H2 Temperatures

No Cooling, Enriched p-H2 Temperatures H3+ + p-H2  H3+ + o-H2 p-H2; J = 0 o-H2; J = 1 ΔE = 170 K

No Cooling, Enriched p-H2 Para-H3+ Fractions

Liquid Nitrogen Cooling (n-H2) : Pressure Dependence H3+ + 2H2  H5+ + H2 High Pressure Low Pressure T ~ 130 K

Liquid Nitrogen Cooling (p-H2): Temperatures

Liquid Nitrogen Cooling (p-H2): para-H3+ Fraction

Concluding Remarks

Acknowledgements Brett McGuire (Emory University) NSF PHY