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Nakamura T, Dangi BB, Wu L, Zhang Y, Schoendorff G, Gordon MS, Yang DS. Spin-orbit coupling of electrons on separate lanthanide atoms of Pr2O2 and its singly charged cation. J Chem Phys 2023; 159:244303. [PMID: 38131482 DOI: 10.1063/5.0185579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 11/27/2023] [Indexed: 12/23/2023] Open
Abstract
Although it plays a critical role in the photophysics and catalysis of lanthanides, spin-orbit coupling of electrons on individual lanthanide atoms in small clusters is not well understood. The major objective of this work is to probe such coupling of the praseodymium (Pr) 4f and 6s electrons in Pr2O2 and Pr2O2+. The approach combines mass-analyzed threshold ionization spectroscopy and spin-orbit multiconfiguration second-order quasi-degenerate perturbation theory. The energies of six ionization transitions are precisely measured; the adiabatic ionization energy of the neutral cluster is 38 045 (5) cm-1. Most of the electronic states involved in these transitions are identified as spin-orbit coupled states consisting of two or more electron spins. The electron configurations of these states are 4f46s2 for the neutral cluster and 4f46s for the singly charged cation, both in planar rhombus-type structures. The spin-orbit splitting due to the coupling of the electrons on the separate Pr atoms is on the order of hundreds of wavenumbers.
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Affiliation(s)
- Taiji Nakamura
- Department of Chemistry and Ames Laboratory, Iowa State University, Ames, Iowa 50011-3111, USA
- Institute for Materials Chemistry and Engineering, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - Beni B Dangi
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA
| | - Lu Wu
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA
| | - Yuchen Zhang
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA
| | - George Schoendorff
- Department of Chemistry and Ames Laboratory, Iowa State University, Ames, Iowa 50011-3111, USA
- Propellants Branch, Rocket Propulsion Division, Aerospace Systems Directorate, Air Force Research Laboratory, AFRL/RQRP, Edwards Air Force Base, California 93524, USA
| | - Mark S Gordon
- Department of Chemistry and Ames Laboratory, Iowa State University, Ames, Iowa 50011-3111, USA
| | - Dong-Sheng Yang
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA
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Zhang Y, Nakamura T, Wu L, Wenjin Cao W, Schoendorff G, Gordon MS, Yang DS. Electronic states and transitions of PrO and PrO+ probed by threshold ionization spectroscopy and spin-orbit multiconfiguration perturbation theory. J Chem Phys 2022; 157:114304. [DOI: 10.1063/5.0113741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The precise ionization energy of praseodymium oxide (PrO) seeded in supersonic molecular beams is measured with mass-analyzed threshold ionization (MATI) spectroscopy. A total of 33 spin-orbit (SO) states of PrO and 23 SO states of PrO+ are predicted by second-order multiconfigurational quasi-degenerate perturbation (MCQDPT2) theory. Electronic transitions from four low-energy SO levels of the neutral molecule to the ground state of the singly charged cation are identified by combining the MATI spectroscopic measurements with the MCQDPT2 calculations. The precise ionization energy is used to reassess the ionization energies and the reaction enthalpies of the Pr + O → PrO+ + e- chemi-ionization reaction reported in the literature. An empirical formula that uses atomic electronic parameters is proposed to predict the ionization energies of lanthanide monooxides, and the empirical calculations match well with available precise experimental measurements.
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Affiliation(s)
- Yuchen Zhang
- Chemistry, University of Kentucky, United States of America
| | - Taiji Nakamura
- Gunma University Faculty of Engineering Graduate School of Engineering Department of Chemistry and Bioengineering, Japan
| | - Lu Wu
- University of Kentucky, United States of America
| | | | - George Schoendorff
- Propellants Branch, Rocket Propulsion Division, Air Force Research Laboratory Aerospace Systems Directorate Edwards AFB, United States of America
| | - Mark S. Gordon
- Department of Chemistry, Iowa State University, United States of America
| | - Dong-Sheng Yang
- Department of Chemistry, University of Kentucky, United States of America
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Tzeng SY, Takahashi K, Tzeng WB. Two-Color Resonant Two-Photon Mass-Analyzed Threshold Ionization of 2,4-Difluoroanisole and the Additivity Relation of Ionization Energy. J Phys Chem A 2020; 124:10517-10526. [DOI: 10.1021/acs.jpca.0c08272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sheng Yuan Tzeng
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, 1 Section 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Kaito Takahashi
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, 1 Section 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Wen Bih Tzeng
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, 1 Section 4, Roosevelt Road, Taipei 10617, Taiwan
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