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Theoretical and Experimental Study of the Spectroscopy and Thermochemistry of UC+/0/–

Journal Article · · Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory
A combination of high-level ab initio calculations and anion photoelectron detachment (PD) measurements is reported for the UC, UC, and UC+ molecules. To better compare the theoretical values with the experimental photoelectron spectrum (PES), a value of 1.493 eV for the adiabatic electron affinity (AEA) of UC was calculated at the Feller–Peterson–Dixon (FPD) level. The lowest vertical detachment energy (VDE) is predicted to be 1.500 eV compared to the experimental value of 1.487 ± 0.035 eV. A shoulder to lower energy in the experimental PD spectrum with the 355 nm laser can be assigned to a combination of low-lying excited states of UC and excited vibrational states. The VDEs calculated for the low-lying excited electronic states of UC at the SO-CASPT2 level are consistent with the observed additional electron binding energies at 1.990, 2.112, 2.316, and 3.760 eV. Potential energy curves for the Ω states and the associated spectroscopic properties are also reported. Compared to UN and UN+, the bond dissociation energy (BDE) of UC (411.3 kJ/mol) is predicted to be considerably lower. The natural bond orbitals (NBO) calculations show that the UC0/+/– molecules have a bond order of 2.5 with their ground-state configuration arising from changes in the oxidation state of the U atom in terms of the 7s orbital occupation: UC (5f27s1), UC (5f27s2), and UC+ (5f27s0). Furthermore, the behavior of the UN and UC sequence of molecules and anions differs from the corresponding sequences for UO and UF.
Research Organization:
Johns Hopkins Univ., Baltimore, MD (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
SC0008501; SC0018921; SC0019317
OSTI ID:
1909836
Journal Information:
Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory, Journal Name: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory Journal Issue: 50 Vol. 126; ISSN 1089-5639
Publisher:
American Chemical SocietyCopyright Statement
Country of Publication:
United States
Language:
English

References (65)

NBO 7.0 : New vistas in localized and delocalized chemical bonding theory journal June 2019
Chemical accuracy in ab initio thermochemistry and spectroscopy: current strategies and future challenges journal January 2012
Quantum electrodynamical corrections to the fine structure of helium journal January 1974
Perturbative corrections to account for triple excitations in closed and open shell coupled cluster theories journal September 1994
A complete active space SCF method (CASSCF) using a density matrix formulated super-CI approach journal May 1980
A fifth-order perturbation comparison of electron correlation theories journal May 1989
A modified definition of the zeroth-order Hamiltonian in multiconfigurational perturbation theory (CASPT2) journal September 2004
Fuels for sodium-cooled fast reactors: US perspective journal September 2007
Fuel development for gas-cooled fast reactors journal September 2007
Uranium carbide properties for advanced fuel modeling – A review journal January 2022
Electronic structures and mechanical properties of uranium monocarbide from first-principles and calculations journal September 2009
Experimental and Computational Description of the Interaction of H and H with U journal June 2022
Electronic Properties of UN and UN from Photoelectron Spectroscopy and Correlated Molecular Orbital Theory journal October 2022
Active Thermochemical Tables: The Adiabatic Ionization Energy of Hydrogen Peroxide journal September 2017
Intermolecular interactions from a natural bond orbital, donor-acceptor viewpoint journal September 1988
An open-shell spin-restricted coupled cluster method: application to ionization potentials in nitrogen journal June 1988
Second-order perturbation theory with a CASSCF reference function journal July 1990
Accurate Ionization Potentials for UO and UO 2 :  A Rigorous Test of Relativistic Quantum Chemistry Calculations journal June 2003
Infrared Spectra and Quantum Chemical Calculations of the Uranium Carbide Molecules UC and CUC with Triple Bonds journal May 2010
Introduction to Active Thermochemical Tables:  Several “Key” Enthalpies of Formation Revisited journal November 2004
Spectroscopic and Theoretical Investigations of UF and UF + journal February 2013
Additive Covalent Radii for Single-, Double-, and Triple-Bonded Molecules and Tetrahedrally Bonded Crystals: A Summary journal September 2014
Accurate Relativistic Small-Core Pseudopotentials for Actinides. Energy Adjustment for Uranium and First Applications to Uranium Hydride journal November 2009
Parallel Douglas–Kroll energy and gradients in NWChem: Estimating scalar relativistic effects using Douglas–Kroll contracted basis sets journal January 2001
RIMS measurements for the determination of the first ionization potential of the actinides actinium up to einsteinium
  • Waldek, Achim
  • RESONANCE IONIZATION SPECTROSCOPY 2000: Laser Ionization and Applications Incorporating RIS; 10th International Symposium, AIP Conference Proceedings https://doi.org/10.1063/1.1405607
conference January 2001
The generalized Douglas–Kroll transformation journal November 2002
Handbook of Basic Atomic Spectroscopic Data journal December 2005
The permanent electric dipole moments and magnetic g factors of uranium monoxide journal November 2006
Infrared spectra and quantum chemical calculations of the uranium-carbon molecules UC, CUC, UCH, and U(CC)2 journal June 2011
The complete active space SCF (CASSCF) method in a Newton–Raphson formulation with application to the HNO molecule journal February 1981
A full coupled‐cluster singles and doubles model: The inclusion of disconnected triples journal February 1982
The full CCSDT model for molecular electronic structure journal June 1987
Gaussian basis sets for use in correlated molecular calculations. I. The atoms boron through neon and hydrogen journal January 1989
The coupled‐cluster single, double, and triple excitation model for open‐shell single reference functions journal October 1990
Photoelectron spectroscopy of metal cluster anions: Cu n , Ag n , and Au n journal November 1990
Second‐order perturbation theory with a complete active space self‐consistent field reference function journal January 1992
Electron affinities of the first‐row atoms revisited. Systematic basis sets and wave functions journal May 1992
Coupled‐cluster methods with noniterative triple excitations for restricted open‐shell Hartree–Fock and other general single determinant reference functions. Energies and analytical gradients journal June 1993
Coupled cluster theory for high spin, open shell reference wave functions journal October 1993
Assessment of Gaussian-2 and density functional theories for the computation of enthalpies of formation journal January 1997
Noniterative energy corrections through fifth-order to the coupled cluster singles and doubles method journal April 1998
Probing the electronic structures of low oxidation-state uranium fluoride molecules UF x ( x = 2−4) journal December 2013
Correlation consistent basis sets for actinides. I. The Th and U atoms journal February 2015
Theoretical spectroscopy study of the low-lying electronic states of UX and UX+, X = F and Cl journal November 2015
Theoretical study of actinide monocarbides (ThC, UC, PuC, and AmC) journal December 2016
Bond dissociation energies of TiC, ZrC, HfC, ThC, NbC, and TaC journal July 2018
The MRCC program system: Accurate quantum chemistry from water to proteins journal February 2020
Spectroscopic and theoretical studies of UN and UN + journal March 2020
Erratum: The NBS tables of chemical thermodynamic properties. Selected values for inorganic and C1 and C2 organic substances in SI units [J. Phys. Chem. Ref. Data 11, Suppl. 2 (1982)] journal October 1989
The Molpro quantum chemistry package journal April 2020
The electron affinity of the uranium atom journal June 2021
Spin-orbit matrix elements for internally contracted multireference configuration interaction wavefunctions journal November 2000
Further benchmarks of a composite, convergent, statistically calibrated coupled-cluster-based approach for thermochemical and spectroscopic studies journal April 2012
Search for effective local model potentials for simulation of quantum electrodynamic effects in relativistic calculations journal March 2003
The Energy Levels of a Rotating Vibrator journal September 1932
Revision of the Douglas-Kroll transformation journal June 1989
Systematic study of the stable states ofC−,Si−,Ge−,andSn−via infrared laser spectroscopy journal October 1998
Ground-state electronic structure of actinide monocarbides and mononitrides journal July 2009
First-principles study of uranium carbide: Accommodation of point defects and of helium, xenon, and oxygen impurities journal January 2010
First-principles study of defect behavior in irradiated uranium monocarbide journal March 2011
Electronic correlation and transport properties of nuclear fuel materials journal November 2011
Effect of spin-orbit and on-site Coulomb interactions on the electronic structure and lattice dynamics of uranium monocarbide journal August 2016
Coupled-cluster theory in quantum chemistry journal February 2007
Production of High-Density Uranium Carbide Compacts for Use in Composite Nuclear Fuels journal August 2008
Fuels for Advanced Nuclear Energy Systems journal January 2009

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