Quantum diffusion controlled chemistry: the H + NO reaction Morgan Balabanoff Anderson Research Group 06.20.2016

Reactions in para-hydrogen matrix pH2 allows for additional reactions with the host Diffusion of H atom (1.8-4.3K) Currently using in bi-molecular reactions pH2 H + H2 → H2 + H

PES of the H+NO reaction H + NO → 1HNO H + NO → 3NOH at our low temperatures we should only see HNO U. Bozkaya, J.M. Turney, Y. Yamaguchi, H.F. Schaefer III, J. Chem. Phys. 136, 164303 (2012).

Outline Previous work 14NO Spectroscopy of isotopically labeled 15NO Kinetics of H + 15NO in pH2

Kinetics of 14NOH and H14NO k = 1.67(3)x10-2 min-1 photolysis bar 3NOH 1HNO 14 NO Describe reaction! NO is reacting - decay explain why we see NOH, didn’t expect to see rate of NO is comparable to rates of NOH and HNO k = 1.52(4)x10-2 min-1 k = 1.67(3)x10-2 min-1 k = 1.72(6)x10-2 min-1 M. Ruzi, D. Anderson, J. Chem. Phys. A 119, 12270 (2015).

PES of the H+NO reaction H + NO → 1HNO H + NO → 3NOH the fact that we are even making NOH! U. Bozkaya, J.M. Turney, Y. Yamaguchi, H.F. Schaefer III, J. Chem. Phys. 136, 164303 (2012).

Outline Previous work 14NO, spectroscopy and kinetics Spectroscopy of isotopically labeled 15NO Kinetics H + 15NO in pH2

Liquid helium bath cryostat Deposit matrix at ~2.5 K Pre-cooled H2 gas and dopant gas Photolyze sample, 193 nm Repeated FTIR scans

Spectroscopy of 15NO in pH2 multiple peaks – rotational fine struction should see only a single peak, suggests rot

Rotation of 15NO in pH2 N=O pH2 should see only a single peak, suggests free rot N=O

Spectroscopy of 15NOH in pH2 OH stretch bend fine structure “interesting” See similar splitting patterns between the 𝜈1 and 𝜈3 peaks

14NOH splittings D C E B F A G ν1 average Relative difference   ν1 average Relative difference ν3 average A 3475.23(1) -0.600 1098.15(2) -0.688 B 3475.54(1) -0.295 1098.49(2) -0.344 C 3475.73(3) -0.100 1098.71(4) -0.122 D 3475.83(5) 1098.84(1) E 3475.98(1) 0.143 1098.96(1) 0.123 F 3476.19(1) 0.351 1099.17(1) 0.334 G 3476.48(2) 0.649 1099.48(3) 0.638 D C E B A F G quantified splittings talk about average roughly symmetric and same for both vibrations of NOH

15NOH splittings D C E B F A G ν1 average Relative difference   ν1 average Relative difference ν3 average A 3474.76(3) -0.601 1087.49(4) -0.640 B 3475.07(1) -0.296 1087.81(1) -0.321 C 3475.26(1) -0.110 1088.04(2) -0.102 D 3475.37(2) 1088.14(1) E 3475.47(1) 0.107 1088.25(1) 0.118 F 3475.67(1) 0.300 1088.45(3) 0.319 G 3475.96(2) 0.598 1088.74(6) 0.601 D C E B A F G see same patterns, comparable betw vibrations work in progress!

Comparison of isotopomers – OH stretch 15 15 15N 14N

Comparison of isotopomers – NOH bend 15 15 14N 15N reproducible on each vibration

Outline Previous work 14NO, spectroscopy and kinetics Spectroscopy of isotopically labeled NO Kinetics H + 15NO in pH2

Kinetics – Photolysis at 4.3K photolysis bar 15 H15NO v2 talk through reaction! similar to regular NO rxn, comparative magnitues

Kinetics – Photolysis at 1.8K 15 H15NO v2

Increasing temperature gradually over ~50 minutes to 4.3K Kinetics – Raising temperature to 4.3K 15 Increasing temperature gradually over ~50 minutes to 4.3K H15NO v2

Increasing temperature gradually over ~50 minutes to 4.3K Kinetics – Raising temperature to 4.3K Increasing temperature gradually over ~50 minutes to 4.3K H15NO v2 15

PES of the H+NO reaction H + NO → 1HNO H + NO → 3NOH see what we originally expected to see only HNO produced when annealed U. Bozkaya, J.M. Turney, Y. Yamaguchi, H.F. Schaefer III, J. Chem. Phys. 136, 164303 (2012).

Comparison of rate constants 14NO average rates at 4.3K 15NO average rates at 4.3K kNO = 1.52(0)x10-2 min-1 kNO = 1.72(1)x10-2 min-1 kNOH = 1.68(6)x10-2 min-1 kNOH = 1.89(2)x10-2 min-1 kHNO = 1.77(4)x10-2 min-1 kHNO = 1.70(2)x10-2 min-1 14NO rate at 1.8K 15NO rate at 1.8K kNO = 0.6(1)x10-2 min-1 kNO = 0.64(4)x10-2 min-1 kNOH = 0.43(6) x10-2 min-1 kNOH = 0.5(5)x10-2 min-1 kHNO = 0.6(2)x10-2 min-1 kHNO = 0.60(9)x10-2 min-1

Conclusions 15NO spectra was collected to gain further information on previous work on 14NO Both have same splitting pattern for NOH Rate constants between isotopomers are comparable Temperature dependence on the H + NO reaction Displays typical “activated” chemistry

Future Work Increase the concentration of HNO and NOH produced to study overtones For kinetics studies, conduct reactions at intermediate temperature open up more spectroscopically with higher concentrations

Thank you Thank you everyone in the Anderson research group and Dr. Anderson for their help and support. This research was funded by the Chemistry Division of the US National Science Foundation (CHE 13-62497)

Questions?

Kinetic temperature dependence

Reaction of H + NO Because NO freely rotates, we see both products pH2 NOH pH2

Kinetics – Photolysis at 4.3K