Detection of the Thorium Dimer via Two-Dimensional Fluorescence Spectroscopy.

Thorium dimer, Th2, has been detected in the gas phase via two-dimensional laser-induced fluorescence electronic spectroscopy. The visible excitation spectra are broad, unstructured features with an approximate line width of 10 cm(-1). The spectrum consists of vibrational progressions associated with excitation from the ground electronic state to two different excited electronic states. The dispersed fluorescence was analyzed to give ground state vibrational constants ωe = 134.86 ± 0.66 cm(-1) and ωexe = 0.50 ± 0.04 cm(-1). Vibrational constants ωe = 169 ± 3 and 212 ± 2 cm(-1) were determined for the two excited electronic states. The radiative lifetimes were measured. A comparison with theoretical predictions is given.

[1]  K. Peterson.  Correlation consistent basis sets for actinides. I. The Th and U atoms. , 2015, The Journal of chemical physics.

[2]  L. Gagliardi,et al.  Quantum chemical calculations and experimental investigations of molecular actinide oxides. , 2015, Chemical reviews.

[3]  T. Steimle,et al.  Branching ratios and radiative lifetimes of the U , L , and I states of thorium oxide , 2014 .

[4]  Zhiyong Zhang.  Spin–orbit DFT with analytic gradients and applications to heavy element compounds , 2014, Theoretical Chemistry Accounts.

[5]  M. Heaven,et al.  Spectroscopy and structure of the simplest actinide bonds. , 2014, The journal of physical chemistry. A.

[6]  T. Steimle,et al.  Stark and Zeeman effect in the [18.6]3.5 - X(1)4.5 transition of uranium monofluoride, UF. , 2014, The Journal of chemical physics.

[7]  Michael Dolg,et al.  Relativistic small-core pseudopotentials for actinium, thorium, and protactinium. , 2014, The journal of physical chemistry. A.

[8]  Trevor W. Hayton,et al.  Recent developments in actinide-ligand multiple bonding. , 2013, Chemical communications.

[9]  A. Gaunt,et al.  Recent developments in synthesis and structural chemistry of nonaqueous actinide complexes. , 2013, Chemical reviews.

[10]  Dongqi Wang,et al.  Recent advances in computational actinoid chemistry. , 2012, Chemical Society reviews.

[11]  Michael Dolg,et al.  Relativistic pseudopotentials: their development and scope of applications. , 2012, Chemical reviews.

[12]  P. Schwerdtfeger.  The pseudopotential approximation in electronic structure theory. , 2011, Chemphyschem : a European journal of chemical physics and physical chemistry.

[13]  D. Dixon,et al.  Matrix infrared spectra and theoretical studies of thorium oxide species: ThOx and Th2Oy. , 2011, The journal of physical chemistry. A.

[14]  C. Cummins,et al.  Towards uranium catalysts , 2008, Nature.

[15]  Laura Gagliardi,et al.  Reaching the maximum multiplicity of the covalent chemical bond. , 2007, Angewandte Chemie.

[16]  B. Roos,et al.  Exploring the actinide-actinide bond: theoretical studies of the chemical bond in Ac2, Th2, Pa2, and U2. , 2006, Journal of the American Chemical Society.

[17]  M. Heaven.  Probing actinide electronic structure using fluorescence and multi-photon ionization spectroscopy. , 2006, Physical chemistry chemical physics : PCCP.

[18]  L. Karlsson,et al.  Resonant two-photon ionization spectroscopy studies of jet-cooled , 1998 .

[19]  L. Karlsson,et al.  The 3Δu−X3Δg band system of jet-cooled Ti2 , 1997 .

[20]  M. Morse,et al.  The 3Π0u ← X 3Δ1g band system of jet‐cooled Ti2 , 1992 .