Download presentation

Presentation is loading. Please wait.

Published byDonovan Doland Modified about 1 year ago

1
The role of asymptotic states in H 3 + Jonathan Tennyson Department of Physics and Astronomy Royal Society University College London Jan 2006 HPCx supercomputer: Daresbury Laboratory

2
Spectroscopy of H 3 + “Solved problem” at low energy How about near dissociation? Nature of (rotation-)vibration states? Radiative association: H 2 + H + H h Isotope exchange eg HD + H 3 + H 2 + H 2 D + Meilke et al, Phys. Rev. Lett. 91, (2003)

3
Accurate H 3 + PES Realistic potential energy surface: Polyansky et al, Mol. Phys., 98, 261 (2000). r R Jacobi coordinates

4
Density of states: requires serious computer power Even states

5
H 3 + near dissociation vibrational state

6

7

8
Calculated rotational constants for H 3 + JJ Munro, J Ramanlal & J Tennyson, New J Phys, 7, 196 (2005)

9

10
r R =90 Classical trajectory at cm -1

11
Poincare surface of section at cm -1 r p

12
Classical trajectory above dissociation r R =90 “Feshbach” resonance

13
Poincare surface of section for D 0 > E > D e

14
Creates H 3 + Detects H + CO 2 laser: 800 – 1000 cm -1 H h H 2 + H + Near-dissociation photodissociation experiment of Carrington et al

15
Quantum states at dissociation: Near dissociation spectrum of H 3 + by Carrington et al discrete lines in 222 cm -1

16

17
Technique for characterising resonances 1.Solve H 0 0 = E 0 for all E including > D 0. 2.Solve H = H 0 + i U(R) for 0 dropping bound solutions; i U(R) is complex absorbing potential (CAP). 3. Vary to identify resonances in complex plane.

18
Continuum wavefunction r R = 90

19
Complex Absorbing Potential (CAP) comparison

20
Position Width Locating resonances using a CAP

21
Vibrational (Feshbach) resonances Width ( ) > 1 cm -1 Too short lived to be important for photodissociation spectrum

22
Shape resonances: rotational states trapped by centrifugal barrier KE release

23
Complete model of H 3 + near-dissociation photodissocation spectrum Vibrational dissociation + above Rotational dissociation + above Resonances: lifetime effects Dipole transitions: spectroscopy Asymptotic Vibrational States (AVS) Robust Present in other (all?) molecules eg O 3, NO 2

24
Bruno Silva Paolo Barletta James Munro ChemReact High Performance Computing Consortium

Similar presentations

© 2016 SlidePlayer.com Inc.

All rights reserved.

Ads by Google