Improved ionization potential of calcium using frequency-comb-based Rydberg spectroscopy (original) (raw)
Related papers
Journal of Physics B: Atomic, Molecular and Optical Physics, 1992
Using a two-step laser optogalvanic technique in a Ca DC discharge the authors have measured the energies of the even 3dnd J=0 and J=2 as well as some 3dng J=2 autoionizing states of Ca in the range below 62500 cm-1, for which calculations have been published. In general the agreement between experimental and theoretical values is very good. Especially important is the detection of the '4p2'1S0 and, probably, the 4p5p3D2 perturbers.
Multiphoton ionization of the calcium atom by linearly and circularly polarized laser fields
Physical Review A, 2010
We theoretically study multiphoton ionization of the Ca atom irradiated by the second (photon energy 3.1 eV) and third (photon energy 4.65 eV) harmonics of Ti:sapphire laser pulses (photon energy 1.55 eV). Because of the dense energy level structure the second and third harmonics of a Ti:sapphire laser are nearly single-photon resonant with the 4s4p 1 P o and 4s5p 1 P o states, respectively. Although two-photon ionization takes place through the near-resonant intermediate states with the same symmetry in both cases, it turns out that there are significant differences between them. The photoelectron energy spectra exhibit the absence or presence of substructures. More interestingly, the photoelectron angular distributions clearly show that the main contribution to the ionization processes by the third harmonic arises from the far-off-resonant 4s4p 1 P o state rather than the near-resonant 4s5p 1 P o state. These findings can be attributed to the fact that the dipole moment for the 4s 2 1 S e -4s5p 1 P o transition is much smaller than that for the 4s 2 1 S e -4s4p 1 P o transition.
Evidence for a non-Rydberg molecular doubly excited state of Ca2
Chemical Physics Letters, 2009
We report experimental and theoretical evidence of a non-Rydberg molecular doubly excited state of Ca 2 involving excited molecular orbitals mixing 4p and 3d characters. The excitation spectrum of Ca 2 , carried by helium or argon clusters, is recorded experimentally in the range 25600-27800 cm −1 , displaying a bimodal structure. The latter is interpreted from ab initio calculation and analysis of the adiabatic states of Ca 2 up to doubly excited asymptotes Ca(4p3d 1 D)+Ca(4s 2 1 S) and Ca(4s3d 3 D)+Ca(4s4p 3 P), and the relevant dipole transition moments. The bimodal structure is assigned as resulting from the avoided crossing between adiabatic states 3 1 Π u and 4 1 Π u , reflecting the mixing of doubly excited configurations and absorbing singly excited configurations.
Resonant electron capture to high Rydberg states of Ca II
Physical review, 1984
The dielectronic recombination cross section for the Ca u ion is calculated for the process in which the 4s electron is excited to the 4p state as the projectile electron is captured to a high Rydberg state (nl). The cross section, averaged over a bin size of 0.3 eV, exhibits a peak of 1.8x10 ' crn, while a cutoff for n~80 reduces this to 2.3x10 ' cm. The recent crossed-beam experiment gives a cross section of 1.8x 10 cm which is at least seven times larger than the theoretical value. '4Y. Hahn, Phys. Rev. A 22, 712 (1984).
Optical resonance detection by field ionization of Rydberg state in colinear laser spectroscopy
Journal de Physique, 1986
2014 Deux nouvelles méthodes efficaces, et non optiques, de détection de résonance optique en spectroscopie colinéaire sont décrites. La première méthode utilise l'ionisation par champ d'un état de Rydberg peuplé à l'aide de deux lasers : le premier est monomode et interagit colinéairement avec le jet d'atomes rapides et le second est multimode et interagit perpendiculairement. En détectant, à la résonance, les ions produits à la place des photons de fluorescence, on obtient une efficacité de 1,1 x 10-5 qui est comparable à la limite de sensibilité habituellement atteinte par la méthode de fluorescence induite par laser. Une deuxième expérience similaire utilise deux lasers à colorant monomodes tous deux interagissant colinéairement avec le faisceau d'atomes rapides. Par comparaison avec la première méthode, on obtient un accroissement de la sensibilité de deux ordres de grandeur (correspondant à une efficacité de 1,2 x 10-3). L'application de ces méthodes à l'étude d'isotopes de courte durée de vie, produits en ligne, est examinée. Abstract 2014 New efficient non-optical detection methods of optical resonances in colinear laser spectroscopy are described. A first method uses the field ionization of a Rydberg state populated by means of two lasers : one is single frequency and interacts colinearly with the fast atomic beam, the other one is multimode and interacts perpendicularly. By detecting, at resonance, the produced ions instead of the fluorescence photons, an overall efficiency of 1.1 x 10-5 has been obtained, which is comparable to the usual sensitivity limit reached by the laser induced fluorescence method. A second similar experiment uses two single mode dye lasers both interacting colinearly with the fast atomic beam. Compared to the first technique an increase of the sensitivity by two orders of magnitude has been obtained (corresponding to an efficiency of 1.2 x 10-3). Application to the study of on line produced short-lived isotopes is discussed.
High-resolution diode-laser spectroscopy of calcium
Applied Physics B Lasers and Optics, 1994
Saturated-absorption signals on the calcium 657 nm transition are observed by direct absorption using diode lasers and a high flux atomic-beam cell. Linewidths as narrow as 65 kHz are observed with a high signal-to-noise ratio. Prospects for using this system as a compact wavelengthifrequency reference are considered.
International Journal of Advanced Research, 2021
We report in this paper energy positions of Rydberg series from metastable state of Ca3+ ion.. Calculations are performed up to n = 20 using the Screening Constant by Unit Nuclear Charge (SCUNC). The present results compared wellwith the experimental data of Ghassan A Alna’washi which are the only available values.The accurate data presented in this work may be a useful guideline for future experimental and other theoretical studies.
Laser gain is reported on the 4p3d 3F -4s3d 3D transitions of Ca at 643.907, 646.257, 647.166, and 649.378 nm following optical pumping of the 4s2 'So -4s4p 3PI intercombination transition at 657.278 nm. The effect is realized through large scale collisional redistribution of energy which rapidly leads to the excitation of higher states and eventual ionization of Ca atoms. Our calculations based on a simple rate equation model suggest that population inversions are a combined result of direct excitation of the upper lasing states through inelastic collisions, and three-body recombination.