Ab initio calculations of the low lying 2  states of NO David W. Schwenke NASA Ames Research Center

Stardust probe entering Earth’s atmosphere Space craft returning to Earth rely on aero-braking to dump kinetic energy. Modeling radiative heating requires opacities for N 2,O 2,N 2 +,O 2 +,NO,NO +,… Thermal Protection System (TPS)

X B (9 Y ij ) C (5 Y ij ) K (5 Y ij ) L (5 Y ij ) Gallusser and Dressler 1982

Adiabatic calculations –standard procedure –complex structure of curves avoided crossings in energy abrupt changes in transition moments spikes in Born-Oppenheimer breakdown terms Diabatic calculations –non-standard –curves are smooth

Procedure (icMRCI, MOLPRO) Diagonalizing H gives adiabatic states –X, C mixed with B,L,… Diagonalizing PHP gives diabatic states –B,L,… Orthogonality gives final states –X,C,B

G&D: BX: CX: 0.31

Conclusions Have a good procedure to give good diabatic states for NO –physical model means non-adiabatic coupling matrix elements are not required –curves can be shifted/scaled to improve agreement with experiment Transition moment is in agreement with experiment Diabatic coupling in ok agreement with experiment