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NaK Lambda doubling and permanent electric dipoles in low-lying (1)Pi states: Experiment and theoryстатья
Информация о цитировании статьи получена из
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
- Авторы: Tamanis M., Auzinsh M., Klincare I., Nikolayeva O., Ferber R., Pazyuk E.A., Stolyarov A.V., Zaitsevskii A.
- Журнал: Physical Review A - Atomic, Molecular, and Optical Physics
- Том: 58
- Номер: 3
- Год издания: 1998
- Издательство: American Physical Society
- Местоположение издательства: United States
- Первая страница: 1932
- Последняя страница: 1943
- DOI: 10.1103/PhysRevA.58.1932
- Аннотация: The paper presents Lambda splittings and q factors in the NaK D (1)II state, directly measured from the electric radio-frequency-optical double resonance (RF-ODR) in laser-induced fluorescence (LIF) for a number of vibrational states v = 1-22 with definite rotational levels J between 7 and 46. Permanent electric dipole moment values (d) have been obtained by measuring in LIF spectra the relative intensities of "forbidden" lines caused by de Stark effect induced elf mixing in the (1)II state, with their subsequent processing, which allowed us to obtain the q/d ratio. A possible influence of the hyperfine structure on the RF-ODR signal and relative intensities has been calculated, showing that this influence can be neglected. The q(v) values exhibited a decrease from q(1) = 1.529x10(-5) cm(-1) to q(22) = 1.171x10(-5) cm(-1), which has been explained by an increase of the difference potential between D (1)II and C (1)Sigma(+) states with internuclear distance (R); the respective L-uncoupling matrix element was evaluated as 1.87. It was shown, both by semiempirical treatment and population analysis of ab initio molecular wave functions, that considerable pi d and sigma d configuration admixtures are present in the D (1)II and the C (1)Sigma(+) states. For the B (1)II state, it was demonstrated that Lambda doubling is caused by two competing perturbers (A (1)Sigma(+) and C (1)Sigma(+)), yielding q factors of similar to-2 x 10(-6) cm(-1), in agreement with high-resolution spectroscopy data given in the Literature; single-configuration approximation is valid for interacting B (1)II(sigma 3s(Na), pi 4p(K))similar to A (1)Sigma(+)(sigma 3s(Na),a4p(K)) states. The measured d(v) values, which varied from 6.6 to 4.6 D, have been used to obtain the empirical D (1)II. state d(R) function for R = 6-12 a.u. by means of an improved instability-free inversion procedure exploiting a special functional form. Two independent series of ab initio all-electron calculations of d(R) and d(v) have been performed for the D (1)II. and B (1)II states of NaK. First, d values were computed as expectation values of the electric dipole operator with conventional multireference configuration-interaction wave functions. Second, the finite-field (FF) technique, combined with a multipartitioning perturbation theory (MPPT) treatment of electronic eigenstates, was applied for the calculation of d(R) functions. The FF-MPPT calculations showed excellent agreement with experimental D (1)II d(v) values obtained in the present work, as well as the proximity to experimental B (1)II d(v) values given in the literature, thus showing that, as distinct from the ground state, it is important to account correctly for effective interactions of valence electrons arising from core-valence correlations, which could not be done properly with previously used pseudopotential techniques. The experimental d and a values dropping out from a smooth v dependence have been considered as perturbed by D (1)II similar to d (3)II interaction and exploited to evaluate respective d(1) and c(1) values for the perturbing d (3)II state.
- Добавил в систему: Пазюк Елена Александровна