Rotationally resolved infrared spectra of the ν 1 and ν 3 N-H stretching vibrations of the Ar-NH 2 + radical ionic complex have been observed by means of photodissociation spectroscopy. The analysis of the rotational structure shows that the complex has a 3 Σ - ground electronic state with a linear or quasi-linear proton-bound structure Ar-H-N-H + characterized by an intermolecular center of mass separation of 3.085 Å. The origins of the ν 1 and ν 3 bands were determined as 2803.65(2) and 3287.36(2) cm -1 , and the frequency of the intermolecular stretch vibration, ν s , as 170.4(6) cm -1 . Ab initio calculations performed at the UMP2 level of theory confirm that the quasi-linearity and the diradical character of NH 2 + in its electronic ground state are not changed upon Ar complexation. The calculated properties of the intermolecular bond of the complex (D e = 1773 cm -1 , R Ar -H ∼ 2.01 Å, ν s ∼ 185 cm -1 ) and the predicted complexation induced frequency shifts for ν 1 and ν 3 are in good agreement with the experimental results.
|Number of pages||8|
|Journal||Journal of Physical Chemistry A|
|Publication status||Published - Dec 3 1998|
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry