NWO Astrochemistry program, Project 3.4: Vibration-rotation inelastic collisions

NWO Astrochemistry Programme, 12 april 2010

Observations

Pontoppidan 2008: Spectroastrometric Imaging of Molecular Gas within Protoplanetary Disk Gaps
Van der Plas 2009: Evidence for CO depletion in the inner regions of gas-rich protoplanetary disks
Najita 1996: Kinematic Diagnostics of Disks around Young Stars: CO Overtone Emission from WL 16 and 1548C27 (Appendix B: Collisional excitation of CO vibrational levels)

Lab, theory

H+CO Potentials

1986 BBH, two-dimensional

1996 (modified)WKS, three-dimensional

Good spectroscopy
Long range not accurate

2007 Shepler, two-dimensional, MRCI+CCSD(T)

Demonstrates that WKS potential has long range problem, gives incorrect J=0->1
Close-coupling on four potentials, BBH, WKS, + new MRCI and CCSD(T)
A & A 475, L15 (2007)

2013 SAG, three-dimensional, CCSD(T)

Accurate spectroscopy
Accurate long range
Confirms Shepler 2007 conclusion

H+CO cross sections and rates

Chu and Dalgarno, Proc. Roy. Soc. London A, 1975

Green and Thaddeus, 1976 (ApJ

Rotational, J=0..7
T=5..100K

2002, Balakrishnan et al ApJ

Basecol data
Vibrational + rotational rates
WKS potential
IOS approximation
CO(v=0, J=0-7) rotational rates
CO(v=1, J=0-4) vibrational quenching
Rates for T = 5 -3000 K

Rotational/vibrational quenching
WKS potential
IOS approximation

2005, Benhui Yang

Vibrational-rotational quenching
WKS potential
CO(v=1,j=0,1,2) - CO(v=0,j)
Close-coupling
State-to-state cross sections and rates
Test against IOS

2013 Benhui Yang, ApJ

Rotational quenching rates
CO(v=0, j)-CO(v=0,j=0), initial state j=1 to 5
2007 Shepler CCSD(T) potential (good long range)
Coupled channels
Data www.physast.uga.edu/~yang/research/hcodatas/hco.html
Data UGA

Modelling CO ro-vibrational emission from Herbig Ae discs

2002 Balakrishnan data
Use scaling laws

Reviews, books

Last updated: October 7, 2009, by Gerrit C. Groenenboom,