Sequential nonadiabatic excitation of large molecules and ions driven by strong laser fields

Journal Article · Thu Jan 01 00:00:00 EST 2004 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.69.013401· OSTI ID:20640618

Markevitch, Alexei N; Levis, Robert J ^[1]; Romanov, Dmitri A ^[2]; Smith, Stanley M; Schlegel, H Bernhard ^[3]; Ivanov, Misha Yu ^[4]

---

1. Department of Chemistry, Center for Advanced Photonics Research, Temple University, Philadelphia, Pennsylvania 19122 (United States)
2. Department of Physics, Center for Advanced Photonics Research, Temple University, Philadelphia, Pennsylvania 19122 (United States)
3. Department of Chemistry, Wayne State University, Detroit, Michigan 48202 (United States)
4. Steacie Institute for Molecular Sciences, NRC Canada, 100 Sussex Drive, Ottawa, ON K1A 0R6 (Canada)

Electronic processes leading to dissociative ionization of polyatomic molecules in strong laser fields are investigated experimentally, theoretically, and numerically. Using time-of-flight ion mass spectroscopy, we study the dependence of fragmentation on laser intensity for a series of related molecules and report regular trends in this dependence on the size, symmetry, and electronic structure of a molecule. Based on these data, we develop a model of dissociative ionization of polyatomic molecules in intense laser fields. The model is built on three elements: (i) nonadiabatic population transfer from the ground electronic state to the excited-state manifold via a doorway (charge-transfer) transition; (ii) exponential enhancement of this transition by collective dynamic polarization of all electrons, and (iii) sequential energy deposition in both neutral molecules and resulting molecular ions. The sequential nonadiabatic excitation is accelerated by a counterintuitive increase of a large molecule's polarizability following its ionization. The generic theory of sequential nonadiabatic excitation forms a basis for quantitative description of various nonlinear processes in polyatomic molecules and ions in strong laser fields.

• OSTI ID: 20640618
• Journal Information: Physical Review. A, Vol. 69, Issue 1; Other Information: DOI: 10.1103/PhysRevA.69.013401; (c) 2004 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ELECTRONIC STRUCTURE
ELECTRONS
EXCITATION
EXCITED STATES
GROUND STATES
LASER RADIATION
MASS SPECTRA
MASS SPECTROSCOPY
MOLECULAR IONS
MOLECULAR STRUCTURE
MOLECULES
NONLINEAR PROBLEMS
PHOTOIONIZATION
PHOTON-MOLECULE COLLISIONS
POLARIZABILITY
POLARIZATION
SYMMETRY
TIME-OF-FLIGHT METHOD