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Molecular Tunneling Ionization and Molecular Alignment. X. M. Tong, Z. X. Zhao and C. D. Lin Physics Department, Kansas State University, Manhattan KS 66506. email: [email protected] http://phys.ksu.edu/~xmtong. Molecular Tunneling Ionization. Motivation: - PowerPoint PPT Presentation
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Molecular Tunneling Ionization and Molecular Alignment
X. M. Tong, Z. X. Zhao and C. D. Lin
Physics Department,Kansas State University, Manhattan KS 66506
email: [email protected] http://phys.ksu.edu/~xmtong
• Motivation:• Ionization; tunneling & multiphoton;• ADK (Ammosov, Delone and Krainov) model;• Experimental observations.
• Theoretical Method:• Molecular orbital at asymptotical region;• Tunneling ionization;• How to compare with experiments?
• Results and Discussion• D2/Ar, N2/Ar, O2/Xe, CO/Kr• S2/Xe, SO/Xe, NO/Xe• F2/Ar
Molecular Tunneling Ionization
Tunneling Ionization
Multiphoton Ionization:
Keldysh parameter
Atoms or Molecules in an Intense Laser Field
Ionization of N2 and Ar
30 fs: Guo et al., PRA 58 (1998) R4271. 100 fs : DeWitt et al., PRL 87 (2001) 153001.
Ip
N2: 15.58 eVAr: 15.76 eV
30 fs: Guo et al., PRA 58 (1998) R4271. 200 fs : Talebpour et al., JPB 29 (1996) L677.
Interference Model:Muth-Bohm et al., PRL 85 (2000) 2280.Failed for D2, F2
Effective Charge:Guo, PRL 85 (2000) 2276.
Ip
O2: 12.36 eVXe: 12.13 eV
Ionization of O2 and Xe
Ionization supression
W.P.T.I.
Atomic Tunneling Ionization
Atomic Tunneling Ionization
Atomic Tunneling Ionization
W.P.T.I.
F
Molecular Tunneling Ionization
A1A2
A3
Molecular Tunneling Ionization
3.5x1014 W/cm2
Ionization Rates of H2+ in a Static Field
F
H2+
z
Saenz, PRA 61(2000) 051402.
Ionization Rates of H2
F
H2
z
Ratio of Ionization Rates for N2:Ar and O2:Xe
F
Tunneling Ionization for Oriented Molecules
X1013 W/cm2
Ionization for Oriented N2 Molecules
X1013 W/cm2
F
Ionization for Oriented O2 Molecules
z
r
How to Compare with Experiments ?
D2/Ar
Ionization Rate, Probability and Signal
D2 Energy Potential
Molecular Vibration Effect
30 fs: Guo et al., PRA 58 (1998) R4271. 100 fs : DeWitt et al., PRL 87 (2001) 153001.
N2/Ar
Ip
N2: 15.58 eVAr: 15.76 eV
30 fs: Guo et al., PRA 58 (1998) R4271. 200 fs : Talebpour et al., JPB 29 (1996) L677.
O2/Xe
Ip
O2: 12.36 eVXe: 12.13 eV
Expt: Wells et al., PRA 66 (2002) 013409.
Ip
D2: 15.47+0.8 eVAr: 15.76 eV
D2/Ar
Expt: Wells et al., PRA 66 (2002) 013409.
Ip
CO: 14.01 eVKr: 14.00 eV
CO/Kr
Expt: 100 fs : DeWitt et al., PRL 87 (2001) 153001.
Ip
F2: 15.70 eVAr: 15.76 eV
F2/Ar
Ip
NO: 9.26 eVS2: 9.36 eVSO: 10.29 eVXe: 12.13 eV
NO/Xe, S2/Xe and SO/Xe
Expt: Wells et al., PRA 66 (2002) 013409.Xe Expt: Guo et al., PRA 58 (1998) R4271.
NO and Xe
Expt: Wells et al., PRA 66 (2002) 013409.Xe Expt: Guo et al., PRA 58 (1998) R4271.
S2 and Xe
Expt: Wells et al., PRA 66 (2002) 013409.Xe Expt: Guo et al., PRA 58 (1998) R4271.
SO and Xe
A1A2
A3
Summary
• Develop a molecular tunneling ionization theory;• Study the diatomic molecular ionization;• Extend to triatomic molecules;• Different suppression mechanisms.
Summary
The full paper can be downloaded fromhttp://www.phys.ksu.edu/~xmtong/pub.html
(2) Molecular Alignment
Fq
(a) Angular dependent ionization signal; (b) How to Align a molecule.
Molecular Alignment in laser field
J. Ortigoso et al., JCP110,3870
Short pulse: revival;Long pulse: No
Molecular Alignment
Initial: Random Kick:
Deposit J
Revival:
Molecular Alignment
F
Molecular Alignment
O2: Wjm = 1 (even J) or 0 (odd J)N2: Wjm = 1/3 (even J) or 2/3 (odd J)
Kick or Push ?
Pulse intensity 2x1013 W/cm2
F t
N2: (2x1013 : 8x1013)
Revival
O2: (2x1013 : 4x1013)
Summary
(a) Optimized revival can be achieved with a fixed laser intensity;(b) 10% to 20% enhancement for O2, and(c) 20% to 60% enhancement for N2;(d) maximum enhancement when the two field parallel.
Summary
