Isolation of stable intermediates in reactive gas mixtures: Rotational spectrum of H3P...Cl2 in a pulsed jet

Abstract

The weakly bound dimer H3P...Cl2 has been isolated in a pulsed jet by keeping the highly reactive components H3P and Cl2 separate until the point at which they expand into the evacuated Fabry–Pérot cavity of a pulsed-nozzle Fourier-transform microwave spectrometer. The rotational spectra of the three symmetric-top isotopomers H3P...35Cl 35Cl, H3P...35Cl 37Cl, and H3P...37Cl 35Cl detected in this way have been analyzed to give the ground-state spectroscopic constants B0, DJ, DJK, χ1(Cl), and χ2(Cl). Comparison of the dimer properties determined from the spectroscopic constants of H3P...Cl2 with those of the hydrogen-bonded dimer H3P...HCl indicates that charge transfer is not predominant in the interaction of PH3 and Cl2. Some parallels in the properties of B...Cl2 and B...HCl are discussed for B=PH3 and HF.

Structures of the van der Waals Isomers of Halosulfuric Acids: Microwave Spectra of HX–SO3(X= F, Cl, Br)

“…While we had hoped that SO 3 would be acidic enough to drive the donoracceptor bond to a clearly observable extent even for the very weakly basic halogen atoms, this is apparently not the case. Thus, the HX-SO 3 are more like the "prereactive" complexes such as O 3 -C 2 H 4 (32) or H 3 P-Cl 2 (33), which have been studied extensively by several groups (16,(32)(33)(34).…”

“…Although in principle, an incipient donor-acceptor interaction could cause a perturbation of the HX subunits, the tensor projection formula should be reasonably applicable here since the complexes appear to be weakly bound. For the SO 3 subunit, an estimate of may be obtained from a recent measurement (18) of the 33 S quadrupole coupling constant in Ar-SO 3 . In that work, the observed coupling constant of the complex was combined in eq.…”

“…In that work, the observed coupling constant of the complex was combined in eq. [3] with an accurate ab initio calculation for the 33 SO 3 monomer to determine ͗cos corresponds to an average angular excursion of 15.6 (ϩ3.3/ Ϫ4.8)°(19). As previously noted (18,20), the amplitude of the zero-point angular oscillations for a given moiety is often fairly constant within a series of related systems.…”

Comparison between standard and counterpoise-corrected optimization using some hydrogen and halogen bonded systems

“…The B Á Á Á X bond lengths have previously been determined by experimental techniques for some dimers [20][21][22][23][24][25][26][27][28][29][30][31][32] Some optimized structures are minimum stationary points at the standard level whereas they are maximum stationary points at the CP-corrected level, and vice versa. For example, linear structures of N 2 Á Á Á HCl and N 2 Á Á Á HBr are ground states by the CP-corrected method and, with negative vibrational frequencies, are transition states by the standard method.…”

Nuclear quadrupole coupling constants in complexes B ··· X2: Sternheimer-type properties of free X2from experimental intramolecular charge shifts

“…Experimental investigations have been carried out for the series B ... C1, with B = CO [l], C,H, [2], C,H, [3], PH, [4], H,S [5], HCN [6] and-NH, [7]. Interpretation of the spectra yields geometries, intermolecular force constants and electric field gradients at the quadrupolar nuclei.…”