Production and Study of Triply Charged Diatomic Ions with Femtosecond Pulses:  Application to

Abstract

Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/eng/view/object/?id=77667172-806f-4b66-a460-e34168ef3387 http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/voir/objet/?id=77667172-806f-4b66-a460-e34168ef3387 Sciences, National Research Council of Canada, 100 Sussex DriVe, Ottawa, Ontario K1A 0R6, Canada ReceiVed: October 24, 2000; In Final Form: January 17, 2001 We describe the preparation of diatomic trications using intense femtosecond laser pulses, and discuss the feasibility of using femtoseond pump-probe techniques to measure the vibrational spectrum of Cl 2 3+ . Initial attempts to observe the vibrational spectra of Cl 2 3+ were unsuccessful. Possible refinements to the experiment are guided by calculations of the electronic states, transition moments, and field-dressed potential curves for Cl 2 3+ . Solution of the time-dependent Schrödinger equation using these theoretical data as input allow an accurate simulation of pump-probe experiments and their time-delay signals. Optimization of the experimental parameters via the simulation suggests an improved approach to obtaining the spectra of trications, with special emphasis on the unusual aspects of these systems. Production and Study of Triply Charged Diatomic Ions with Femtosecond Pulses

Simulation of pump–probe spectroscopy of a highly-charged diatomic molecule: Role of intermediate charged states and electronic and vibrational excitation in the multiple ionization of Cl2 and strong-field spectroscopy of Cl23+

“…This approach to describing ionization can be easily adapted to include enhanced ionization 19-21 by using the appropriate instantaneous tunneling rate from the upper quasistatic surface. In the present study, enhanced ionization does not contribute to the pump-probe signal since Cl 2 3ϩ is dissociative beyond 5 bohr, 3 i.e., at R significantly shorter than the critical distance R c Ϸ8 -10 bohr.…”

“…From analysis of the results, we discuss the conditions under which femtosecond pumpprobe spectroscopy can be used to observe the vibrational spectra of diatomic trications such as Cl 2 3ϩ , whose time-offlight mass spectrum has been observed recently. 3 The formation of metastable trications either by strong laser pulses or by electron impact has been previously studied experi-mentally and theoretically ͑e.g., Ref. 4͒.…”

“…Next, the number of trication molecules arriving at a time-of-flight mass spectrometer is detected. 3 Depending on the delay time between the pump and probe pulses, the probe pulse will dissociate a variable fraction of the trications created by the pump pulse. The resulting modulation in the number of undissociated trications can, in principle, be Fourier-transformed to yield the vibrational spectrum of the trication.…”

“…3 Based on the experimental data and the theoretical simulations, it was proposed 3 that a relatively weak but long tail of the intense pump pulse will dissociate excited vibrational states of the trication, leaving the bound population predominantly in the ground vibrational state. Since the resulting state is stationary, modulation in the pump-probe signal is reduced significantly.…”

Photodissociation ofBr2molecules in an intense femtosecond laser field

“…Halogen and halogen compounds can damage the atmo sphere ozone layer [30,31], and therefore their molecular photodissociation process under the laser field has been an active field for many years [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26], especially for the halogen diatomic molecules Cl2, Br2, and I2 [32][33][34][35][36][37][38], In this paper, we experimentally demonstrate the photodissociation process of Br2 molecules in the intense femtosecond laser field by a dcsliced ion velocity map imaging technique. Our experimental results show that four fragment ions Br"+ in = 1-4) can be observed, and their kinetic energy (KE) increases while their angular distribution decreases with the increase of the charge number.…”