HPO does not follow Walsh’s rules! Improved molecular structures from the spectroscopy of jet-cooled HPO and DPO

Self Cite

The Ã(1)A('')-X̃(1)A(') electronic spectrum of the jet-cooled transient molecule HAsO and its deuterated isotopologue has been observed for the first time by pulsed discharge jet laser spectroscopy. The techniques of laser-induced fluorescence and single vibronic level emission were employed to probe the electronic properties of the species. The bending and AsO stretching frequencies have been determined in both states. A rotational analysis of the 0(0)(0) bands of both HAsO and DAsO has been completed and the following effective (r(0)) structures were derived: r(")(HAs) = 1.576(3) Å, r(")(AsO) = 1.8342(5) Å, and θ(") = 101.5(4)°; and r(')(HAs) = 1.569(4) Å, r(')(AsO) = 1.7509(9) Å, and θ(') = 93.1(10)°. In the rotational analysis, lines induced by axis-tilting were observed, and calculated spectra with an axis tilting angle of 3.0(5)° reproduced the intensity of these lines. The change in geometry on electronic excitation is similar to that observed for the molecule HPO, with an increase in the X-O bond length and a decrease in the HXO angle, but contrary to the predictions of the Walsh diagram for generic HAB triatomic molecules. Our ab initio calculations show that the correlation between orbital energy and bond angle changes upon electronic excitation, resulting in the atypical angle change.

Section: A Molecular Structuresupporting

confidence: 67%

The electronic spectrum of the previously unknown HAsO transient molecule

Grimminger

Clouthier

2011

Self Cite

“…The 22 In thẽ B excited state, the bond length is 1.671 Å, comparable to a typical PO single bond and consistent with promotion of an electron from the π to the π * molecular orbital, which decreases the bond order.…”

supporting

confidence: 56%

Heavy atom nitroxyl radicals. VI. The electronic spectrum of jet-cooled H2PO, the prototypical phosphoryl free radical

Gharaibeh

Clouthier

Tarroni

2011

Self Cite

The previously unknown electronic spectrum of the H(2)PO free radical has been identified in the 407-337 nm region using a combination of laser-induced fluorescence and single vibronic level emission spectroscopy. High level ab initio predictions of the properties of the ground and first two excited doublet states were used to identify the spectral region in which to search for the electronic transition and were used to aid in the analysis of the data. The band system is assigned as the B̃(2)A(')-X̃(2)A(') electronic transition which involves promotion of an electron from the π to the π∗ molecular orbital. The excited state r(0) molecular structure was determined by rotational analysis of high resolution LIF spectra to be r(PO) = 1.6710(2) Å, r(PH) = 1.4280(6) Å, θ(HPO) = 105.68(7)°, θ(HPH) = 93.3(2)°, and the out-of-plane angle = 66.8(2)°. The structural changes on electronic excitation, which include substantial increases in the PO bond length and out-of-plane angle, are as expected based on molecular orbital theory and our previous studies of the isoelectronic H(2)AsO, Cl(2)PS, and F(2)PS free radicals.

“…7 The HPCl ground state r e z bond lengths are slightly larger than the corresponding r e bond lengths of the PHϭ1.4221 Å and PClϭ2.014 609(49) Å diatomic molecules, 35,36 which have correspondingly larger vibrational frequencies ( e : PHϭ2365.2 cm Ϫ1 , PCl ϭ551.4 cm Ϫ1 ).…”

Section: ͑8͒mentioning

confidence: 91%

“…We recently reported the laser-induced fluorescence and emission spectra and molecular structure of HPO, an important intermediate in the chemiluminescence of white phosphorus. 7 In the present work, we have turned our attention to the little known HPCl free radical.…”

Section: Introductionmentioning

confidence: 99%

The electronic spectroscopy and molecular structure of the HPCl free radical: A potential III–V semiconductor growth intermediate

Tackett

Evans

et al. 2003

Self Cite

Articles you may be interested inThe complex spectrum of a "simple" free radical: The A ̃ -X ̃ band system of the jet-cooled boron difluoride free radical J. Chem. Phys. 135, 094305 (2011); 10.1063/1.3624528The ground state energy levels and molecular structure of jet-cooled HGeCl and DGeCl from single vibronic level emission spectroscopyPulsed discharge jet spectroscopy of DSiF and the equilibrium molecular structure of monofluorosilyleneThe Ã 2 AЈ -X 2 AЉ electronic spectra of jet-cooled HPCl and DPCl have been obtained for the first time using the pulsed electric discharge technique with a precursor mixture of PCl 3 and H 2 or D 2 . From a combination of laser-induced fluorescence and wavelength resolved emission spectra, all of the vibrational frequencies in the ground and excited states of both isotopomers have been measured and vibrational force fields have been determined. Rotational analyses of the 0 0 0 bands of both isotopomers showed small doublet splittings characteristic of an asymmetric top molecule with a single unpaired electron. From the rotational constants and the force fields, estimated equilibrium structures were derived with rЉ(PH)ϭ1.4158 (23) Å, rЉ(PCl)ϭ2.0388(23) Å, Љϭ95.02(27)°, and rЈ(PH)ϭ1.4067(20) Å, rЈ(PCl)ϭ2.0050(2) Å, and Јϭ115.53(12)°. The experimental data firmly establish that the observed spectra and those previously obtained by chemiluminescence techniques ͓Bramwell et al., Chem. Phys. Lett. 331, 483 ͑2000͔͒ are due to the HPCl free radical.