The ionization energy of C2.

Authors :: Krechkivska, O.
Bacskay, G. B.
Welsh, B. A.
Nauta, K.
Kable, S. H.
Stanton, J. F.
Schmidt, T. W.
Source :: Journal of Chemical Physics; 2016, Vol. 144 Issue 14, p1-6, 6p, 3 Charts, 3 Graphs
Publication Year :: 2016
Abstract: Resonant two-photon threshold ionization spectroscopy is employed to determine the ionizationenergy of C<subscript>2</subscript> to 5 meV precision, about two orders of magnitude more precise than the previously accepted value. Through exploration of the ionization threshold after pumping the 0-3 band of the newly discovered 4³Π<subscript>g</subscript>←a³Π<subscript>u</subscript> band system of C<subscript>2</subscript>, the ionizationenergy of the lowest rovibronic level of the a³Π<subscript>u</subscript> state was determined to be 11.791(5) eV. Accounting for spin-orbit and rotational effects, we calculate that the ionizationenergy of the forbidden origin of the a³Π<subscript>u</subscript> state is 11.790(5) eV, in excellent agreement with quantum thermochemical calculations which give 11.788(10) eV. The experimentally derived ionizationenergy of X¹Σ<subscript>g</subscript><superscript>+</superscript>X¹Σ<subscript>g</subscript><superscript>+</superscript> state C<subscript>2</subscript> is 11.866(5) eV. [ABSTRACT FROM AUTHOR]