Ab initio calculation of harmonic force fields and vibrational spectra for the phosphine oxides and sulfides R3PY (R = H, F, CH3; Y = O, S)

Abstract

we can in. each case specify the optical density x55 that corresponds to a particular spectrum (see legends).A comparison between the PH5 spectra in Figures 4 and 5 reveals that improvements in the basis set beyond the 6-31G** level change the predicted spectrum only very slightly. The vt and v6 bands, which overlap strongly around 1200 cm'1, are coupled by a second-order Coriolis interaction (|f46| = 0.35, 6-31G**); including this interaction in the simulation leads to a reduced intensity of the Q branch of v4 and to some changes in the fine structure that are not shown presently. With regard to the dipole-forbidden transitions in PH5, the a/ bands cannot gain intensity by second-order Coriolis effects being coupled to e" only,

Line Intensities of the Phosphine Dyad at 10 μm

“…ν 2 and ν 4 dipole moment derivatives and their relative signs; their values were lower than the normalized values obtained by Tarrago et al (14). The only other considerations of the dyad intensities were a computation of the electric dipole moment derivatives by Chong and Papousek (23) and two ab initio calculations (24,25). Recently, an ab initio force field calculation was obtained in order to determine a potential energy surface for PH 3 (26).…”

Adsorption of Organophosphate Pesticides with Humic Fraction-Immobilized Silica Gel in Hexane

“…Such a competition also revealed the nature or type of interaction leading to the adsorption in hexane. The nature of the bonding between phosphorus and oxygen, or sulfur elements in phosphine oxides 43−55 and thiophosphenes, 55−57 has been of great interest, and thus, extensively reviewed over the years; however, it remains controversial because no virtual d orbitals are involved in the bond resonance between structures R 3 P + O − , or S − ↔ R 3 PO, or S based on several theoretical calculations. 55,58−69 In addition, the overall experimental results indicate that the phosphoryl bond is strong, short, and polar.…”

Ab initiostructures and quartic force fields of phosphine oxide and phosphine sulphide

“…Previous theoretical values reported in ref. [5] are shown in parentheses. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 Table 6: Calculated MP2/cc-pCVTZ quartic anharmonic force fields of OPH 3 and SPH 3 in symmetry coordinates, as defined in Table 3.…”

“…Phosphine oxide, OPH 3 and phosphine sulphide, SPH 3 , together with their tautomers HOPH 2 , HSPH 2 and halogen derivatives have been extensively studied in several theoretical papers [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] These studies were mainly focused on the molecular structure and the nature of the P-X (X=O,S) bond [1,2,4,10,13,15], on the tautomerization energetics and reaction paths [1,9,14,15,17] and on vibrational spectra [1,3,[5][6][7][8] Comparatively, much less experimental work has been done. To date, only the Argon matrix infrared spectrum of OPH 3 has been observed [18], while the identification of SPH 3 from a similar experiment [19] has failed.…”