An adjustment of the Ne*2(3P0,2-1S 0) potentials to thermal-energy scattering data

Daunant, I. Colomb de; Vassilev, G.; Baudon, J.; Stern, B.

doi:10.1051/jphys:01982004304059100

Cited by 16 publications

(7 citation statements)

References 17 publications

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“…The result of the latter calculation is consistent with the result of a quantum-mechanical calculation by Leung et al [13]. However, the comparison of the calculated optical-absorption shift at the surface with experimental data [26], as well as scattering data obtained by Colomb de Daunant et al [27], showed that V CS is too repulsive at intermediate distances (3-5 Å). Also the desorption energies from our calculation (0.33 eV), which may also be regarded as a test for the validity of the repulsive part of the potential, are larger than the measured values for the 3 P 2 state.…”

supporting

confidence: 87%

Molecular-dynamics simulation of ejection processes in electronically excited solid Ne

Dutkiewicz¹,

Pędrys²,

Schou³

1996

Europhys. Lett.

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supporting

confidence: 87%

Molecular-dynamics simulation of ejection processes in electronically excited solid Ne

Dutkiewicz¹,

Pędrys²,

Schou³

1996

Europhys. Lett.

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“…A good realization of these criteria can be obtained with a combination of a Born- In the lowest part of the potential well this Morse potential nearly has the same shape as the 3X: potential calculated by Grein et al [24]. I n the outer region it is very similar to the 3Xi potential of Colomb de Daunant et al [25] (see Fig. 2).…”

Section: Tha Potential Curvesmentioning

confidence: 77%

Time‐Resolved Investigation of the Ne Luminescence

Seitfudem¹

1987

Physica Status Solidi (b)

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Solid Ne condensed a t a temperature of 7 K is excited with a pulsed electron beam. The resulting emission spectra are recorded during the excitation pulse and in the time range from 0 to 2.3 ms after excitation. Relative contributions from the different vibrational levels are fitted t o the Nez emissions, measured a t various times after the excitation. A nearly constant contribution from the 0th vibrational level is found which can be explained by complete relaxation of the 0; excimer state. The degree of relaxation and the decay time of the luminescence contributions from the higher vibrational levels change within the 2.3 ms. It is proposed that the 1, state of Ne emits from lattice sites a t one vacancy, two vacancies, and from regular lattice sites.Aufgedampftes Ne wird bei einer Temperatur von 7 K mit einem gepulsten Elektronenstrahl angeregt. Die entstehenden Emissionsspektren werden wahrend des Anregungspulses und im Bereich zwischen 0 und 2,3 ms nach der Anregung aufgenommen. Die zu unterschiedlichen Zeiten nach der Anregung gemessenen Nez-Spektren werden durch relative Beitrage aus den einzelnen Vibrationsniveaus angepant. Es ergibt sich ein nahezu konstanter Beitrag aus dem 0. Vibrationsniveau, der mit der vollstandigen Relaxation des 0;;-Zustands erklart werden kann. Der Relaxationsgrad und die Abklingzeit der Beitrage aus den hoheren Vibrationsniveaus verandern sich innerhalb der 2,3 ms. Zur Deutung dieses Effekts wird vorgeschlagen, daO es sich um Nez-Emissionen aus dem 1,-Zustand an einer Leerstelle, zwei Leerstellen sowie von regularen Gitterplatzen handelt.

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“…have modified the CS potentials and have calculated, by a Jeffreys-Wentzel-Kramers-Brillouin (JWKB) approximation, the scattering amplitudes/ g and/ u (symmetric and antisymmetric), in good agreement with the observed cross sections. 12 We used here the metastability-exchange cross section v e = i I / u -/g 1 2 and the direct one o d = \ I f u +/ g 1 2 deduced from these calculations. In the case when the colliding atoms are of the same isotopic species, indistinguishability does not allow us to separate the two processes.…”

mentioning

confidence: 99%

Elastic Collision Kernels: Theoretical Determination and Direct Observation by Use of Time-Resolved Saturation Spectroscopy in Metastable Neon

1982

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Collision kernels describing elastic collision effects in saturation spectroscopy are completely calculated for the metastable 3 P 0 state of neon, starting from true experiment-deduced potentials. Collision processes with and without metastability exchange are respectively considered. A direct observation of these two kernels is provided by a two-laser time-resolved saturated absorption experiment. They are in good agreement with theory.PACS numbers: 34.40.+n, 32.70.Jz Line shapes in saturation spectroscopy are strongly affected by collisions. As in linear spectroscopy they are sensitive to quenching collisions and to dephasing collisions (broadening and shift), but in addition, as was pointed out early on, they are sensitive to velocity changing collisions (VCC). Many theoretical and experimental works have been devoted to this subject.The quantity of interest is the collision kernel W(v'-*v) which describes the probability per unit time that a collision will change the projection of the atomic velocity on the laser beam axis from v' to v. Many theoretical papers deal with the formal determination of the kernel from scattering amplitudes (sometimes from the interatomic potentials) and with the evaluation of the line shape from the kernel. 1 " 5 Nevertheless in all detailed calculations of line shapes phenomenological potentials (hard sphere, 3 R" 6 , 5 Lennard-Jones) or phenomenological kernels (Keilson and Storer 6 ) are used. In this paper, we present the first attempt to link all the steps from a realistic potential to a direct experimental observation of the kernel. The metastable 3 P 0 level of neon (ls 3 in Paschen notation) has been considered, since the Ne*-Ne potentials had been calculated and the differential cross sections measured.Experimentally the situation is comparable: Many experiments have been performed, but they have been interpreted with phenomenological kernels (strong or weak collisions 6 ). Furthermore in several cases the observed background (strong collisions) or the broadening of saturation peaks (weak collisions) is actually produced by several collisions for each atom and does not clearly represent the kernel.In our experiments we used a transient method previously described, 7 which has been improved to allow the recording of the saturation line shape after a very short time delay following the switching on of the saturating beam. Thus, the observed signal is the result of only one collision per atom. Another novel feature of this work lies in the calculation of a metastability exchange kernel and in its experimental observation in a mixture of two isotopes.Because of its short lifetime, the upper level of the transition (2p 2 for the 613.3-nm line or 2/> 5 for the 626.6-nm line) provides a negligible contribution to the saturation signal. On the other hand, when a collision changes the velocity of an atom that is in a coherent superposition of both levels, this coherence is destroyed, since very different interatomic potentials are involved 8 (except for very small scattering angl...

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An adjustment of the Ne*2(3P0,2-1S 0) potentials to thermal-energy scattering data

Cited by 16 publications

References 17 publications

Molecular-dynamics simulation of ejection processes in electronically excited solid Ne

Molecular-dynamics simulation of ejection processes in electronically excited solid Ne

Time‐Resolved Investigation of the Ne Luminescence

Elastic Collision Kernels: Theoretical Determination and Direct Observation by Use of Time-Resolved Saturation Spectroscopy in Metastable Neon

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