Perturbation of the Ba 6sn s1S0sequence by the 5d7d,3P0state probed by lifetime measurements

Aymar, M; Grafstrom, P; Levison, C; Lundberg, Hans; Svanberg, Sune

doi:10.1088/0022-3700/15/6/013

Cited by 41 publications

(11 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Similar perturbations are observed in many different situations like in the alkaline-earth atoms where perturbations of Rydberg series by isolated levels considerably modify the lifetime values (see, e.g. Bhatia et al (1981) and Aymar et al (1982)). Baylis (1979a, 1979b) have demonstrated that correlation effects between valence and core electrons can be approximated by core-polarization corrections in relativistic single-configuration Hartree-Fock computations of oscillator strengths.…”

Section: Introductionsupporting

confidence: 69%

Lifetimes along perturbed Rydberg series in neutral thallium

Biémont

Palmeri

Quinet

et al. 2005

J. Phys. B: At. Mol. Opt. Phys.

Self Cite

View full text Add to dashboard Cite

Radiative lifetimes of 15 Tl I levels belonging to the 6s 2 ns 2 S 1/2 (n = 7-14) and 6s 2 nd 2 D 3/2 Rydberg series (n = 6-12) have been measured using a time-resolved laser-induced fluorescence technique. All the measured levels have been excited from the ground state 6s 2 6p 2 P 0 1/2 (odd parity) with a single-step excitation process. The general perturbation of the ns series by the 6s6p 2 configuration and the corresponding modification of the lifetimes are adequately reproduced by a theoretical model including core-polarization effects and combined with a least-squares fit to the observed energy levels. The general behaviour of the lifetime values for the 6s 2 np odd levels along the Rydberg series is also well reproduced. The use of the multiconfiguration quantum defect theory has allowed us to obtain lifetime values along the 6s 2 ns 2 S 1/2 series up to levels with n = 31.

show abstract

Section: Introductionsupporting

confidence: 69%

Lifetimes along perturbed Rydberg series in neutral thallium

Biémont

Palmeri

Quinet

et al. 2005

J. Phys. B: At. Mol. Opt. Phys.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Experimental measurements of radiative lifetimes for some even-parity levels [13][14][15][16][17][18][19][20][21] and calculations for the 6snf 3 F 2 (11 n 35) Rydberg series and some 6s6p, 6s7p, 5d5p, and 5d6p levels [22,23] have been reported. But because it is difficult or impossible to excite most of the high-lying odd-parity levels from the ground level 1 S 0 and because the lowest metastable levels 6s5d 3 D J (J = 1 to 3) located above 9000 cm −1 are difficult to populate in a thermal atomic beam, direct lifetime measurements for such levels are scarce.…”

Section: Introductionmentioning

confidence: 99%

Radiative-lifetime measurements and calculations of odd-parity highly excited levels in Ba i

et al. 2010

View full text Add to dashboard Cite

Natural radiative lifetime measurements have been performed for 70 odd-parity highly excited levels of neutral barium in the energy range from 308 15.512 to 417 59.93 cm −1 by a time-resolved laser-induced fluorescence technique in a laser-produced plasma. The lifetime values measured in this paper are in the range from 11.3 to 901 ns. They are compared with the published lifetimes of four levels. Two of them are in good agreement, whereas for the other two our measurements are slightly longer than the published data. The reasons for the discrepancies are discussed. Comparisons with theoretical results of the Hartree-Fock method with relativistic corrections illustrate the difficulties associated with the use of Cowan's codes for obtaining accurate branching fractions for transitions depopulating highly excited levels along the Rydberg series of heavy neutral elements. This work will be useful to extend the set of oscillator strengths available in Ba I.

show abstract

“…раздел 4.2). Полученные в [36,37] во-вторых, удоона при создании оанка данных по радиационным време-нам жизни для ЭВМ. Константы т 0 , г, щ для СЗ (1.1) рассчитаны по зна-чениям т (рек) для каждого состояния серии, полученных статистической обработкой всех имеющихся в настоящее время литературных значений Тк для данного состояния.…”

Section: поправки к квазиклассическимunclassified

“…Лишь для атома гелия и атомов щелочных металлов известны в настоящее время значения т к для состоя-ний с главным квантовым числом до 20 [35,36]. В связи с этим в науч-ной литературе [6,[37][38][39][40] предложено использовать различные экстра-поляционные схемы для оценок времен жизни состояний с большим п. Подбирается некоторый тип аналитической зависимости т к = /с (п*) для описания экспериментально (или теоретически) полученных значений Тк внутри фиксируемой серии уровней. По нижним состояниям опреде-ляются подгоночные параметры С, входящие в /с, после чего /с (/г*) экст-раполируется на неисследованные вышележащие состояния серии.…”

Section: экстраполяционные схемы для нахожденияunclassified

“…В других случаях при выборе /с приходится допускать про-извол. В результате как в условиях ОП [39], так и в приближениях, использующих многоканальную теорию квантового дефекта для расчета x ft [37,40], был «потерян» логарифмический по энергии член ~(1п п* 2 )/п* 2 (см. (3.13)), который играет существенную роль для относительно слабо-излучающих состояний.…”

Section: экстраполяционные схемы для нахожденияunclassified

See 1 more Smart Citation