Quantum and classical dynamics of a diatomic molecule in laser fields with frequency in the region producing maximum dissociation

Dimitriou, KI; Constantoudis, V; Mercouris, Th; Komninos, Y; Nicolaides, CA

dc.contributor.author	Dimitriou, KI	en
dc.contributor.author	Constantoudis, V	en
dc.contributor.author	Mercouris, Th	en
dc.contributor.author	Komninos, Y	en
dc.contributor.author	Nicolaides, CA	en
dc.date.accessioned	2014-03-01T01:26:57Z
dc.date.available	2014-03-01T01:26:57Z
dc.date.issued	2007	en
dc.identifier.issn	1050-2947	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/18307
dc.subject	Diatomic Molecule	en
dc.subject.classification	Optics	en
dc.subject.classification	Physics, Atomic, Molecular & Chemical	en
dc.subject.other	Hamiltonians	en
dc.subject.other	Multiphoton processes	en
dc.subject.other	Photodissociation	en
dc.subject.other	Probability	en
dc.subject.other	Schrodinger equation	en
dc.subject.other	Vibrational spectra	en
dc.subject.other	Classical dynamics	en
dc.subject.other	Diatomic molecule	en
dc.subject.other	Laser fields	en
dc.subject.other	Laser frequency	en
dc.subject.other	Multiphoton dissociation	en
dc.subject.other	Laser pulses	en
dc.title	Quantum and classical dynamics of a diatomic molecule in laser fields with frequency in the region producing maximum dissociation	en
heal.type	journalArticle	en
heal.identifier.primary	10.1103/PhysRevA.76.033406	en
heal.identifier.secondary	http://dx.doi.org/10.1103/PhysRevA.76.033406	en
heal.identifier.secondary	033406	en
heal.language	English	en
heal.publicationDate	2007	en
heal.abstract	By solving nonperturbatively the equations of Schrodinger and of Hamilton, we have studied the time-dependent multiphoton dissociation of a diatomic molecule induced by a moderate low-frequency laser field. The photodissociation probabilities are calculated and analyzed as a function of the laser frequency, the intensity, and the pulse shape. A well-established quantum and classical result is that for laser intensities of the order of 10(14) W/cm(2) the dissociation probability presents a maximum at the frequency omega(max)similar to(0.80-0.90)omega(01), where omega(01) is the transition frequency from the ground to the first excited vibrational state (redshift phenomenon). In this work, we go further and explore the quantum and classical effects of radiation at the optimum frequency omega(max) on the overall vibrational excitation and dissociation dynamics. First, it is shown that both quantum and classical results predict that omega(max) continues to be the optimum frequency for photodissociation even at the order of 10 TW/cm(2), i.e., low intensities. The quantum results show a multipeak structure versus laser frequency, which is attributed to resonant multiphoton transitions, while the classical results show a smooth curve with a broad maximum at omega(max) which is explained by phase space arguments. Second, it is found that in both quantum and classical approaches omega(max) marks a transition in the effects of turn-on time of the pulse shape on dissociation probability: for omega <omega(max) the gradual turn-on of the field leads to a noticeable reduction of the photodissociation probability, while for omega>omega(max) this effect is of minor importance. A classical interpretation of this finding is given, which is based on stickiness effects in phase space. Finally, the crucial role of omega(max) is further demonstrated in the time dependence of bound-state occupation probabilities. The total survival probability decreases faster with time for omega <omega(max) rather than for omega>omega(max). Further, for omega>omega(max) the bound-state occupation probabilities exhibit multiphoton Rabi-type oscillations where more than two vibrational states are involved. These phenomena are predicted by both quantum and classical dynamics, although there are secondary differences which are revealed and discussed.	en
heal.publisher	AMER PHYSICAL SOC	en
heal.journalName	Physical Review A - Atomic, Molecular, and Optical Physics	en
dc.identifier.doi	10.1103/PhysRevA.76.033406	en
dc.identifier.isi	ISI:000249786000109	en
dc.identifier.volume	76	en
dc.identifier.issue	3	en