Electric Field Induced Dissociation of Molecules in Rydberg-like Highly Vibrationally Excited Ion-Pair States

Martin, J. D. D.; Hepburn, J. W.

doi:10.1103/physrevlett.79.3154

Cited by 75 publications

(50 citation statements)

References 49 publications

(48 reference statements)

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“…Exact numerical solution of two-electron molecules H 2 [16,17] [20]. Such states have large dipole moments equal to the internuclear distance R, and thus can lead to large radiative interactions, V(R) ϭ ER, exceeding molecular dissociation energies at current laser intensities.…”

Section: Introductionmentioning

confidence: 99%

Attosecond localization of electrons in molecules

Bandrauk

Chelkowski

Nguyen

2004

Int J of Quantum Chemistry

144

107

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Numerical solutions of the time-dependent Schrödinger equation for a 1Dmodel non-Born-Oppenheimer H 2 ϩ are used to illustrate the nonlinear nonperturbative response of molecules to intense (I Ն 10 13 W/cm 2 ), ultrashort (t Ͻ 10 fs) laser pulses. Molecular high-order harmonic generation (MHOHG) is shown to be an example of such response and the resulting nonlinear photon emission spectrum is shown to lead to the synthesis of single attosecond (10 Ϫ18 s) pulses. Application of such ultrashort pulses to the H 2 ϩ system results in localized electron wavepackets whose motion can be detected by asymmetry in the photoelectron spectrum generated by a subsequent probe attosecond pulse, thus leading to measurement of electron motion in molecules on the attosecond time scale.

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Section: Introductionmentioning

confidence: 99%

Attosecond localization of electrons in molecules

Bandrauk

Chelkowski

Nguyen

2004

Int J of Quantum Chemistry

144

107

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“…A remarkable difference from other potentials is the infinite number of bound states of nuclear motion (rovibrational states) supported close to the dissociation threshold; potentials associated with a covalent bond typically show an asymptotic shape of V n ϳ 1͞r n with n 3 6 and consequently support a finite number of bound states. A connection between the standard treatment of molecules on the one hand, using potentials of electronic states and quantized nuclear motion described by vibrational and rotational quantum numbers y and J, and an ion-pair Rydberg model on the other was established by identifying the effective principal quantum number n with y 1 J 1 1 while the angular momentum of the Rydberg system ᐉ corresponds to J [2].Ion-pair states have been observed in two different regimes: deep in the potential [3,4], where the ionic electron configuration is only approximate due to a major interaction with covalent configurations, and at threshold, where no structure within the ion-pair configuration is observed [5]. Threshold-ion-pair-production spectroscopy (TIPPS) has been used to determine the ion-pair dissociation limit in H 2 [6].…”

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confidence: 99%

“…Ion-pair states have been observed in two different regimes: deep in the potential [3,4], where the ionic electron configuration is only approximate due to a major interaction with covalent configurations, and at threshold, where no structure within the ion-pair configuration is observed [5]. Threshold-ion-pair-production spectroscopy (TIPPS) has been used to determine the ion-pair dissociation limit in H 2 [6].…”

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confidence: 99%

Observation of Coherent Wave Packets in a Heavy Rydberg System

Reinhold

Ubachs

2001

Phys. Rev. Lett.

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Coherent dynamical behavior is observed in the heavy Rydberg system H 1 H 2 . Because of the large mass, time scales of the wave-packet evolution are orders of magnitude slower than for a Rydberg electron. In the presence of a weak electric field, wave packets made up of about 1000 Stark states are excited by near-Fourier transform limited nanosecond laser pulses. Pulsed-field dissociation reveals coherent time evolution on a microsecond time scale, observed as oscillations with frequencies explained by a linear Stark model applied to the H 1 H 2 system. DOI: 10.1103/PhysRevLett.88.013001 PACS numbers: 33.80.Rv, 33.55.Be, 03.65.Ge Studies of the quantum behavior of the infinite series of states associated with a 1͞r potential usually focus on the prototypical Rydberg atom [1], which consists of a heavy positively charged ionic particle and a light negatively charged particle, the Rydberg electron, attracting each other via the Coulomb potential ͑V c ϳ 1͞r͒. The quantized energy levels of such a system are represented by the Rydberg formula:where R is the Rydberg constant, n is the principal quantum number, and d is the quantum defect. The value of the Rydberg constant for an atomand hence the level density is nearly equal for all atoms, because m͞m e m A 1 ͑͞m A 1 1 m e ͒ ഠ 1 for all atoms; the same holds for electronic Rydberg states of molecules in which case the core is a molecular cation.This Letter deals with molecular Rydberg states of a different kind, which may be called "Rydberg states of nuclear motion," which are associated with the Coulomb potential between separated charges of heavy mass, referred to as ion-pair potentials. The large reduced mass m of such a system leads to a value of R ion-pair ͑m͞m e ͒R`orders of magnitude larger than the atomic Rydberg constant; in the case of an H 1 H 2 ion-pair system, m ͑1͞2͒M H results in an increase of the Rydberg constant by 3 orders of magnitude. Notice that in accordance with Eq. (1) binding energies and also level separations for a given quantum number become larger, while separations at a given energy become smaller, therewith opening a range for investigations on the behavior in the 1͞r potential and the transition from quantum to classical behavior.Coulomb potentials of ion-pair systems can also be viewed as a class of molecular potentials describing an ionic bond. A remarkable difference from other potentials is the infinite number of bound states of nuclear motion (rovibrational states) supported close to the dissociation threshold; potentials associated with a covalent bond typically show an asymptotic shape of V n ϳ 1͞r n with n 3 6 and consequently support a finite number of bound states. A connection between the standard treatment of molecules on the one hand, using potentials of electronic states and quantized nuclear motion described by vibrational and rotational quantum numbers y and J, and an ion-pair Rydberg model on the other was established by identifying the effective principal quantum number n with y 1 J 1 1 while the angular moment...

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“…It will be difficult to access this region ðE b ¼ 0-3000 cm À1 Þ by transitions directly from the ground state or through intermediate states using optical double resonance techniques. However, as noted above, access is known to be possible through electronic Rydberg states which are coupled to many of the ion-pair states; this approach is the basis of the Threshold Ion-pair Production Spectroscopy (TIPS) [24] and Zero Ion Kinetic Energy (ZIKE) techniques [25,26]. This high energy region, where HR states are found to be long-lived (s $ 10 À6 s), can also be studied using pulsed excitation techniques to prepare a coherent superposition of states and observing the evolution of the wave packets thus produced [27,28].…”

Section: Heavy Rydberg Analysismentioning

confidence: 99%