CI-MBPT and Intensity-Based Lifetime Calculations for Th II
Lifetime calculations of Th II J = 1.5 and 2.5 odd states are performed with configuration–interaction many-body perturbation theory (CI-MBPT). For many J = 2.5 states, lifetimes are quite accurate, but two pairs of J = 2.5 odd states and many groups of J = 1.5 states are strongly mixed, making theo...
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| Format: | Article |
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MDPI AG
2020-12-01
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| Series: | Atoms |
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| Online Access: | https://www.mdpi.com/2218-2004/8/4/87 |
| _version_ | 1827701018577600512 |
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| author | Igor M. Savukov |
| author_facet | Igor M. Savukov |
| author_sort | Igor M. Savukov |
| collection | DOAJ |
| description | Lifetime calculations of Th II J = 1.5 and 2.5 odd states are performed with configuration–interaction many-body perturbation theory (CI-MBPT). For many J = 2.5 states, lifetimes are quite accurate, but two pairs of J = 2.5 odd states and many groups of J = 1.5 states are strongly mixed, making theoretical predictions unreliable. To solve this problem, a method based on intensities is used. To relate experimental intensities to lifetimes, two parameters, one an overall coefficient of proportionality for transition rates and one temperature of the Boltzmann distribution of populations, are introduced and fitted to minimize the deviation between theoretical and intensity-derived lifetimes. For strongly mixed groups of states, the averaged lifetimes obtained from averaged transition rates were used instead of individual lifetimes in the fit. Close agreement is obtained. Then intensity branching ratios are used to extract individual lifetimes for the strongly mixed states. The resulting lifetimes are compared to available directly measured lifetimes and reasonable agreement is found, considering limited accuracy of intensity measurements. The method of intensity-based lifetime calculations with fit to theoretical lifetimes is quite general and can be applied to many complex atoms where strong mixing between multiple states exists. |
| first_indexed | 2024-03-10T14:24:54Z |
| format | Article |
| id | doaj.art-0d88880e5ad04c20b5bcc21ec728b9ea |
| institution | Directory Open Access Journal |
| issn | 2218-2004 |
| language | English |
| last_indexed | 2024-03-10T14:24:54Z |
| publishDate | 2020-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Atoms |
| spelling | doaj.art-0d88880e5ad04c20b5bcc21ec728b9ea2023-11-20T23:04:15ZengMDPI AGAtoms2218-20042020-12-01848710.3390/atoms8040087CI-MBPT and Intensity-Based Lifetime Calculations for Th IIIgor M. Savukov0Los Alamos National Laboratory, Los Alamos, NM 87545, USALifetime calculations of Th II J = 1.5 and 2.5 odd states are performed with configuration–interaction many-body perturbation theory (CI-MBPT). For many J = 2.5 states, lifetimes are quite accurate, but two pairs of J = 2.5 odd states and many groups of J = 1.5 states are strongly mixed, making theoretical predictions unreliable. To solve this problem, a method based on intensities is used. To relate experimental intensities to lifetimes, two parameters, one an overall coefficient of proportionality for transition rates and one temperature of the Boltzmann distribution of populations, are introduced and fitted to minimize the deviation between theoretical and intensity-derived lifetimes. For strongly mixed groups of states, the averaged lifetimes obtained from averaged transition rates were used instead of individual lifetimes in the fit. Close agreement is obtained. Then intensity branching ratios are used to extract individual lifetimes for the strongly mixed states. The resulting lifetimes are compared to available directly measured lifetimes and reasonable agreement is found, considering limited accuracy of intensity measurements. The method of intensity-based lifetime calculations with fit to theoretical lifetimes is quite general and can be applied to many complex atoms where strong mixing between multiple states exists.https://www.mdpi.com/2218-2004/8/4/87actinidesradiative lifetimesCI-MBPTTh II |
| spellingShingle | Igor M. Savukov CI-MBPT and Intensity-Based Lifetime Calculations for Th II Atoms actinides radiative lifetimes CI-MBPT Th II |
| title | CI-MBPT and Intensity-Based Lifetime Calculations for Th II |
| title_full | CI-MBPT and Intensity-Based Lifetime Calculations for Th II |
| title_fullStr | CI-MBPT and Intensity-Based Lifetime Calculations for Th II |
| title_full_unstemmed | CI-MBPT and Intensity-Based Lifetime Calculations for Th II |
| title_short | CI-MBPT and Intensity-Based Lifetime Calculations for Th II |
| title_sort | ci mbpt and intensity based lifetime calculations for th ii |
| topic | actinides radiative lifetimes CI-MBPT Th II |
| url | https://www.mdpi.com/2218-2004/8/4/87 |
| work_keys_str_mv | AT igormsavukov cimbptandintensitybasedlifetimecalculationsforthii |