Spectroscopy of CrF: Rotational analysis of the B 6Π–X 6Σ+ band system in the 1.2 μm region

Abstract

The B 6Π–X 6Σ+ band system of the CrF radical has been recorded in emission with FTS techniques in the region between 6965 and 9240 cm−1, using a resolution of 0.025 cm−1. A rotational analysis including the (0,0), (1,1), (1,0), (0,1) and (1,2) bands of this system has been carried out, and a set of molecular parameters has been derived for the B 6Π state. The present analysis has also resulted in substantially better determined values for the λ and γ parameters of the X 6Σ+ ground state. An improved set of molecular parameters has been derived for the previously analyzed, heavily perturbed A 6Σ+ state. The present analysis gives strong support for the interpretation that the local perturbations in the v=0–3 levels of A 6Σ+ are due to interactions with the vibrational levels v=3–6 of the B 6Π state. Earlier suggestions involving a low-lying 4Π state as the dominating perturber of the A 6Σ+ state must now be considered as erroneous. A previously suggested interpretation of the 7400 cm−1 band as being possibly due to a quartet transition has also been shown to be in error. The derived first order spin-orbit parameter value of B 6Π [A=47.0382(18) cm−1] and the equilibrium bond distances of X 6Σ+ [1.7839 Å], A 6Σ+ [1.8919 Å], and B 6Π [1.8277 Å] have been discussed, and it has been proposed that the 9σ (Cr4s–4p) molecular orbital of CrF is slightly bonding, while 4π (Cr3dπ) is nonbonding and 10σ (Cr3dσ) antibonding.

Spectroscopy of NbO: Characterization of the Doublet Manifold

“…The e 2 F and f 2 P i states, as well as two vibrational levels of an additional V Å 5 2 state. Molecular parameters of all analyzed procedure of picking out and numbering rotational lines used in previous publications (15,31) was also applied in the states are presented in Tables 3-8. The higher order effective present work.…”

Rotational analysis of the $3_0^1 $31 band of the $\tilde A{}^6\Sigma ^ + \leftarrow \tilde X{}^6\Sigma ^ + $Ã6Σ+←X̃6Σ+ system of CrCCH

“…The expected ground electronic state of CrCCH,X 6 + , is strongly supported by elementary considerations of chemical bonding, by computational chemistry, and by comparison to the closely related chemical species CrH, 39,40 CrF, 38,41,42 CrCl, 43,44 and CrCN, 45 all of which have 6 + ground states. Accordingly, we consider no other possibilities for the ground state symmetry.…”

“…Likely candidates for a second electronic state in this region are the a 4 + state that perturbs the A 6 + state of CrH 36,37 or the B 6 state that perturbs the A 6 + states of CrH and CrF. 37,38 A list of the measured band frequencies is provided in Table II, along with excited state lifetime measurements for the more intense features in the spectrum. These were obtained using the time-delayed resonant two photon ionization method, as described in our article on the fluorescence lifetime of CrH.…”

Vibronic spectroscopy of unsaturated transition metal complexes: CrC2H, CrCH3, and NiCH3

“…The ground state of NiH is now known to be 2 ⌬ 5/2 , and there is extensive spinorbit mixing between the higher energy 2 ⌺ ϩ and 2 ⌸ 1/2 states and between the 2 ⌸ 3/2 and 2 ⌬ 3/2 states. 56 All five of these states lie within 5000 cm Ϫ1 of the ground state, 56 and it is expected that a similar manifold of five states arising from a 3d Ni 9 2 configuration will be present in NiCH 3 . The 2 E state calculated to be the ground state of NiCH 3 derives from a d 2 d 4 d␦ 3 2 configuration analogous to the NiH 2 ⌬ ground state.…”