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Why multiphoton exitations(?); advantages/disadvantages One color experiments / data

II. Multi- photon excitation / ionization processes. Why multiphoton exitations(?); advantages/disadvantages One color experiments / data Experimental methods: Multiphoton ionization (MPI & REMPI) Data interpretations / theory: “What to see and what not to see(?)” Results / examples:

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Why multiphoton exitations(?); advantages/disadvantages One color experiments / data

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  1. II. Multi- photon excitation / ionization processes • Why multiphoton exitations(?); advantages/disadvantages • One color experiments / data • Experimental methods: Multiphoton ionization (MPI & REMPI) • Data interpretations / theory: “What to see and what not to see(?)” • Results / examples: • - characterization of state properties / energies • - (2+1) vs (3+1) REMPI • - ”New” states observed • - analysis of complicated spectra • - state interactions • - multi-photon absorption “mechanism” • - energy distribution in molecules • - polyatomic molecules • Two color experiments / data

  2. Simulation: i(3D2) <- X(1S+) (0,0)

  3. Simulation: Be´/ Bf´ = 7.975/7.969 ±0.030cm-1 De´/Df´= (0.55/0.50 ± 0.10)x10-3 cm-1 n0 = 78625 ± 2 cm-1 E´(J) = B´J(J+1) – D´J2(J+1)2 n0 = E´(v´=0) – E´´(v´´=0) for i(3D2) <- X(1S+) (0,0)

  4. Fig. 2 (2+1) REMPI spectra of I2: I2; [2P1/2]c6s;1g <-<- X 0g (v1,v0)

  5. DOP Fig. 3 I2; [2P1/2]c6s;1g <-<- X 0g (2+1) REMPI spectra of I2: as well as Rotational line series: O: J-2 <- J; P: J-1 <- J Q: J <- J R: J+1 <- J; S: J+2 <- J Exp. Calc. (v1,v0) = Dn / cm-1

  6. AB+ + e : AB** |i4> |i3> Properties of AB* and AB: - energy configurations - molecular geometries |i2> |i1> AB i.e.:

  7. II. Multi- photon excitation / ionization processes • Why multiphoton exitations(?); advantages/disadvantages • One color experiments / data • Experimental methods: Multiphoton ionization (MPI & REMPI) • Data interpretations / theory: “What to see and what not to see(?)” • Results / examples: • - characterization of state properties / energies • - (2+1) vs (3+1) REMPI • - ”New” states observed • - analysis of complicated spectra • - state interactions • - multi-photon absorption “mechanism” • - energy distribution in molecules • - polyatomic molecules • Two color experiments / data

  8. HBr: 16

  9. Total angular momentum changes For W´=0 W ´´=0: J-3;N J-2;O J-1;P J:Q J+1;R J+2;S J+3;T DJ = ±1 DJ = ±1 DJ = ±1 J z = 0

  10. DJ = ±1,.. ,±n; n = odd; DW = 0 DJ = 0 ,±2,.. ,±n; n = even DW = 0 HBr: 16

  11. II. Multi- photon excitation / ionization processes • Why multiphoton exitations(?); advantages/disadvantages • One color experiments / data • Experimental methods: Multiphoton ionization (MPI & REMPI) • Data interpretations / theory: “What to see and what not to see(?)” • Results / examples: • - characterization of state properties / energies • - (2+1) vs (3+1) REMPI • - ”New” states observed • - analysis of complicated spectra • - state interactions • - multi-photon absorption “mechanism” • - energy distribution in molecules • - polyatomic molecules • Two color experiments / data

  12. 18 B´= 8.39±0.05 cm-1 D´= (0.85±0.10)x10-3cm-1 n0 = 82837±3 cm-1

  13. W´=3(F) W´=2(D) W´=1(P) W´=0(S) 2xhn 3xhn 3xhn ½i > 1xhn 2xhn 3xhn “New” state: L1F3 (n0 = 82837±3 cm-1) W´´=0(S) “New” state, not detected before: 19 Predicted state ((s2p3)5dd) in this region: L1F3 (n0 = ?????)

  14. II. Multi- photon excitation / ionization processes • Why multiphoton exitations(?); advantages/disadvantages • One color experiments / data • Experimental methods: Multiphoton ionization (MPI & REMPI) • Data interpretations / theory: “What to see and what not to see(?)” • Results / examples: • - characterization of state properties / energies • - (2+1) vs (3+1) REMPI • - ”New” states observed • - analysis of complicated spectra • - state interactions • - multi-photon absorption “mechanism” • - energy distribution in molecules • - polyatomic molecules • Two color experiments / data

  15. Complicated spectra, analyses / Example I: HCl, (3+1) REMPI: n cm-1 3 x (1/l=333 nm)

  16. n cm-1 Find “difference spectra” / “exp. – Calc.” HCl, (3+1) REMPI / Simulation: ???!! ???!! ???!! OK OK

  17. “Difference spectra(1)” / “exp. – Calc.”: exp. - calc. 3 x (1/l=333 nm) HCl, (3+1) REMPI exp. – calc./ “Diff.sp.(1)” n cm-1

  18. Difference spectra(2) = “exp. – diff. spectra(1)” / Simulation:

  19. “Difference spectra “(1) / Simulation:

  20. Complicated spectra, analyses / Example II: (2,0) -band

  21. NO z z W= 3/2 W= 1/2 1 z Spin-rot. interaction D 2S: Orbit-rot. interaction X 2P: Spin-orbit interaction

  22. (1,1) (1,2) (2,1) (2,2) E1´ E2´ 2S Spin-rot. interaction Cv´ 2P3/2 Orbit-rot. interaction 2P1/2 Av´´=0 Cv´´=0 E1´´ E2´´

  23. 2S (11) (22) (12) (21) 2P , T=298K (2,0)

  24. (2,0)

  25. (2,0)

  26. II. Multi- photon excitation / ionization processes • Why multiphoton exitations(?); advantages/disadvantages • One color experiments / data • Experimental methods: Multiphoton ionization (MPI & REMPI) • Data interpretations / theory: “What to see and what not to see(?)” • Results / examples: • - characterization of state properties / energies • - (2+1) vs (3+1) REMPI • - ”New” states observed • - analysis of complicated spectra • - state interactions • - multi-photon absorption “mechanism” • - energy distribution in molecules • - polyatomic molecules • Two color experiments / data

  27. AB#/A#+B# State interactions/ AB** <->AB# & dissociation processes AB** -> A# + B# ? AB+ + e AB** : |i4> |i3> |i2> |i1> AB

  28. HCl; (3+1)REMPI j3S0- <- X1S+ (0,0) ?

  29. j3S0- <- X1S+ (0,0) (3+1)REMPI ? Comparison of (2+1) og (3+1)REMPI: ?

  30. State interaction / perturbation j <->V(1S+) / interaction strength explanation: 8 7 v´=24 (3+1)REMPI

  31. Rotational perturbation observed in vibrational band due to the transition I2; [2P3/2]c5s;1g <-<- X 0g, v1 = 0, v0 = 1 :: Because of state interactions: [2P3/2]c5s;1g <-> D´(2g)

  32. II. Multi- photon excitation / ionization processes • Why multiphoton exitations(?); advantages/disadvantages • One color experiments / data • Experimental methods: Multiphoton ionization (MPI & REMPI) • Data interpretations / theory: “What to see and what not to see(?)” • Results / examples: • - characterization of state properties / energies • - (2+1) vs (3+1) REMPI • - ”New” states observed • - analysis of complicated spectra • - state interactions • - multi-photon absorption “mechanism” • - energy distribution in molecules • - polyatomic molecules • Two color experiments / data

  33. AB+ + e : AB** |i4> |i3> |i2> Mechanism of nxhn absorption / ionization; involvement of intermediate states. ? |i1> AB

  34. N,T: I µm32s3 P,R: I µm12s1 + m32s3 I(N,T) / I(P,R) depend on m12 and m32 or m12 /m32 Adjust m12 and m32 to obtain best fit: W´´=0(S) W´=0(S) W´´=0(S) 20 I µm12s1 + m32s3

  35. HCl, E(1S+) X(1S+), (3+1)REMPI 21 m12 /m32 = 0.90±0.15

  36. W´=1 (P) W´=0 (S) W´=0 (S) Four paths: W´´=0(S) W´´=0(S) 22

  37. Major path for HCl: E(1S+) X(1S+): Paths vs m12 and m32 : 23 -vs exp.: m12 /m32 = 0.90±0.15

  38. II. Multi- photon excitation / ionization processes • Why multiphoton exitations(?); advantages/disadvantages • One color experiments / data • Experimental methods: Multiphoton ionization (MPI & REMPI) • Data interpretations / theory: “What to see and what not to see(?)” • Results / examples: • - characterization of state properties / energies • - (2+1) vs (3+1) REMPI • - ”New” states observed • - analysis of complicated spectra • - state interactions • - multi-photon absorption “mechanism” • - energy distribution in molecules • - polyatomic molecules • Two color experiments / data

  39. HBr Surface science studies/ collaboration work with J.C. Polanyi, Toronto: Na

  40. Surface science studies/ collaboration work with J.C. Polanyi, Toronto: Na effect? i.e.: 1) hn + NaBrH(s) -> NaBr(s) + H(g)

  41. detect / measure HBr by REMPI: observe kinetic energy. Surface science studies/ collaboration work with J.C. Polanyi, Toronto: Na effect? i.e.: 2) hn + NaBrH(s) -> Na(s) + HBr#(g)

  42. IREMPI n

  43. 2 x (1/l=255nm) 3 x (1/l=382nm) (3+1)REMPI simpler spectrum / “more convenient” wavelength

  44. i.e.: »straight line 25oC (3+1)REMPI spectra and s useful to determine N(J) Line fit Besta beina lína

  45. II. Multi- photon excitation / ionization processes • Why multiphoton exitations(?); advantages/disadvantages • One color experiments / data • Experimental methods: Multiphoton ionization (MPI & REMPI) • Data interpretations / theory: “What to see and what not to see(?)” • Results / examples: • - characterization of state properties / energies • - (2+1) vs (3+1) REMPI • - ”New” states observed • - analysis of complicated spectra • - state interactions • - multi-photon absorption “mechanism” • - energy distribution in molecules • - polyatomic molecules • Two color experiments / data

  46. 3dpF1Su+ <-<-<- X1Sg + V. Blanchet et al., J. Chem. Phys., 119(7), 3751, (2003):

  47. II. Multi- photon excitation / ionization processes • Why multiphoton exitations(?); advantages/disadvantages • One color experiments / data • Experimental methods: Multiphoton ionization (MPI & REMPI) • Data interpretations / theory: “What to see and what not to see(?)” • Results / examples: • - characterization of state properties / energies • - (2+1) vs (3+1) REMPI • - ”New” states observed • - analysis of complicated spectra • - state interactions • - multi-photon absorption “mechanism” • - energy distribution in molecules • - polyatomic molecules • Two color experiments / data

  48. AB = CdAr: (v1,v0) |1> A30+<- X10+ v1+1 v1 v1-1 Energy v0 |0> r (A-B)

  49. (v1,v0) AB = I2: |1> v1+1 [2P1/2]c6s;1g <-<- X 0g v1 v1-1 Energy v0 |0> r (A-B)

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