In:
The Journal of Chemical Physics, AIP Publishing, Vol. 141, No. 20 ( 2014-11-28)
Abstract:
The electronic spectra of Mn+(H2O) and Mn+(D2O) have been measured from 30 000 to 35 000 cm−1 using photodissociation spectroscopy. Transitions are observed from the 7A1 ground state in which the Mn+ is in a 3d54s1 electronic configuration, to the 7B2 (3d54py) and 7B1 (3d54px) excited states with T0 = 30 210 and 32 274 cm−1, respectively. Each electronic transition has partially resolved rotational and extensive vibrational structure with an extended progression in the metal−ligand stretch at a frequency of ∼450 cm−1. There are also progressions in the in-plane bend in the 7B2 state, due to vibronic coupling, and the out-of-plane bend in the 7B1 state, where the calculation illustrates that this state is slightly non-planar. Electronic structure computations at the CCSD(T)/aug-cc-pVTZ and TD-DFT B3LYP/6-311++G(3df,3pd) level are also used to characterize the ground and excited states, respectively. These calculations predict a ground state Mn-O bond length of 2.18 Å. Analysis of the experimentally observed vibrational intensities reveals that this bond length decreases by 0.15 ± 0.015 Å and 0.14 ± 0.01 Å in the excited states. The behavior is accounted for by the less repulsive px and py orbitals causing the Mn+ to interact more strongly with water in the excited states than the ground state. The result is a decrease in the Mn-O bond length, along with an increase in the H-O-H angle. The spectra have well resolved K rotational structure. Fitting this structure gives spin-rotation constants ɛaa″ = −3 ± 1 cm−1 for the ground state and ɛaa′ = 0.5 ± 0.5 cm−1 and εaa′ = −4.2 ± 0.7 cm−1 for the first and second excited states, respectively, and A′ = 12.8 ± 0.7 cm−1 for the first excited state. Vibrationally mediated photodissociation studies determine the O-H antisymmetric stretching frequency in the ground electronic state to be 3658 cm−1.
Type of Medium:
Online Resource
ISSN:
0021-9606
,
1089-7690
Language:
English
Publisher:
AIP Publishing
Publication Date:
2014
detail.hit.zdb_id:
3113-6
detail.hit.zdb_id:
1473050-9
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