Millimeter-Wave Spectra,ab InitioCalculations, and Structures of Fluorophosphane and Chlorophosphane

Abstract

The structures of fluorophosphane, PH2F, and chlorophosphane, PH2Cl, have been calculated ab initio at the SCF, MP2, CCSD, and CCSD(T) levels using a quadruple ζ polarized basis set. Equilibrium and ground state rotational constants as well as centrifugal distortion constants have been predicted for several isotopomers of PH2F and PH2Cl. Theoretical CCSD(T) geometries were also determined for the series of PH n X3 - n (X = F, Cl; n = 0−3) molecules using a triple ζ polarized basis set. The millimeter-wave spectra of the short-lived molecules PH2F, PH2Cl, and their perdeuterated species were measured in the frequency range 100−470 GHz. For PH2F and PH2Cl, accurate ground state parameters have been obtained by a combined fit of the millimeter-wave data and the infrared ground state combination differences. The r o, r z, and r e structures of PH2F and PH2Cl, as well as PH3, PCl3, and PHF2 have been determined. The experimental results are found in excellent agreement with their ab initio predictions.

High-Resolution Infrared Spectrum of PH2Br: Rotational Analysis of the ν3 and ν4 Bands

“…The shift may be accounted for either by diagonal upper state parameters or by an off-diagonal matrix element ζ a 3,6 ; see Eq. [5]. In order to allow comparison with the ab initio calculations we have decided to include a-Coriolis resonance in model 1 and constrained ζ a 3,6 to the ab initio prediction, −0.0376 for both isotopic species.…”

“…Following the first mention of PH 2 I which, according to NMR studies, was reported to be a product of the scrambling reaction between PH 3 and PI 3 in CS 2 (1) or CFCl 3 (2), and the detection of PH 2 F among the products of the reaction of PH 3 with F 2 in an Ar matrix at 16 K (3), we have initiated a broad experimental study to characterize the whole PH 2 X family by rotational and high-resolution infrared spectroscopy. These experimental studies were closely accompanied by ab initio theoretical calculations providing structures and spectroscopic parameters on the basis of the harmonic and anharmonic force fields (4)(5)(6)(7). The concerted efforts allowed to measure the millimeter-wave (MMW) spectra of PH 2 F (5), PH 2 Cl (5), PH 2 Br (8), and PH 2 I (9), and some of their isotopic species and to record and analyze high-resolution FTIR spectra of PH 2 F (6, 10), PH 2 Cl (6, 10), and PH 2 I (9).…”

“…Several reasons are responsible for this deficiency. First, in contrast to PH 2 F and PH 2 Cl, the bromo species cannot be prepared by reaction of PH 3 F 2 with Lewis-acidic bromides (5,6,10). Second, the feasible gas phase reaction of P 2 H 4 with HBr yielding PH 3 and PH 2 Br proceeds only slowly.…”

Rotational Spectra of the Isotopic Species of Chloroform: Experimental andAb InitioStructures

“…We also investigated whether the MP2 method is accurate enough to calculate a bond angle. There is already a lot of evidence that, in most cases, the MP2 method is not significantly worse than much more expensive methods like CCSD(T) for instance (56). Furthermore the good agreement between MP2/6-31G** and HF/6-31G** is a good indication that taking into account the electron correlation is not important (at least in the particular case of chloroform).…”

Complexes H2CO:PXH2and HCO2H : PXH2for X=NC, F, Cl, CN, OH, CCH, CH3, and H: Pnicogen Bonds and Hydrogen Bonds

“…Even though PFH 2 is an unstable molecule, its experimental geometry has been determined by a combination of millimeterwave and infrared spectroscopy. [1] In 2011, Zahn, Frank, Hey-Hawkins and Kirchner [2] used the PFH 2 molecule in the first theoretical study of the pnicogen bond. Soon afterwards, we employed this molecule along with related molecules PXH 2 [3] to investigate the homodimers (PXH 2 ) 2 , and used the coupling constants 1p J(PÀ P) to assist in characterizing the pnicogen bond.…”