Eighth Condensed Phase and Interfacial Molecular Science (CPIMS)

(about 7.3 D). Our studies have provided the first gas-phase spectra of any kind for this
molecule and show that it does indeed have an ΩO=3/2 ground state, consistent with the
calculated 2 Δ3/2 ground state. Our rotationally resolved studies also provide r0O = 1.6180(3) C, in
reasonable agreement with the calculated value of reO=1.636 C. We plan to pursue a
collaboration with Prof. Tim Steimle at Arizona State University to measure the dipole moment
of this unusual molecule, to see if the unusually large calculated value is correct.
While investigating the spectra of VC, we also observed spectroscopic transitions in the
VN molecule, which was probably formed due to residual NH3 in the instrument from a previous
experiment on UN. Although this molecule has been well-studied, we nevertheless found
several transitions that have not previously been observed. We anticipate that this will permit
one or more new excited states of this molecule to be identified.
We have also begun work to collect and analyze the spectrum of UN. As expected, the
molecule has a complicated vibronic spectrum due to the large number of possible arrangements
of electrons in the 5f, 6d, and 7s orbitals. Preliminary rotationally resolved studies suggest that
the ground state of the molecule may have Ω= 3.5 with a bond length of approximately 1.76 Å,
but further work is in progress to obtain a definitive result.
Figure 5 and 6. Low resolution spectrum of UN, showing complicated vibronic structure, and high
resolution spectrum of the 18352 cm -1 band.
III. Future Plans
A. R2PI and DF spectroscopy of transition metal carbides and radicals
Projects for the upcoming year include: (1) Completion of the analysis of the spectra of
VC, VN, CuCCH, and CrCCH, and publication of the results; (2) Additional scans of the spectra
of UN to find bands that are clean and unperturbed, for a determination of the ground state
symmetry and bond length; (3) Dispersed fluorescence of UN to locate low-lying excited
electronic states; (4) Search for the electronic spectrum of ThO2; (5) Search for electronic
spectra of ThC and UC; (6) Collaboration with Prof. Steimle on the electric dipole moments of
VC and UN.
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