Manifestation of interaction of the transition dipole moments in IR spectra of low-temperature liquids and solutions in liquefied noble gases

Dimerization constant of SF6 and CF4 in cryosolutions

“…A distinguishing characteristic of these spectra is the large splitting value Dm (Dm $ 20 cm À1 ) of a strongly IR-active vibration m 3 . To interpret the effect observed, models have been proposed in which the dominant mechanism for the splitting Dm has been associated with the resonance dipole-dipole interaction (RDDI) [10][11][12][13]. The contribution of the additional dipole-induced-dipole interaction (DIDI) is shown to be very small [6,11], and equals 0.1-0.3 cm À1 for (SF 6 ) 2 and (CF 4 ) 2 [6].…”

“…In Ref. [13] it was shown that the RDDI effect on the overtone and combination bands which include a strongly IR-active mode can be equal or even more pronounced than in the corresponding fundamental region.…”

Resonance dipole–dipole coupling and Fermi resonance in CF4 dimers

“…), that is manifested in the appropriate spectral regions [10][11][12]. In the spectra of liquid CF 4 the Fermi resonance leads to appearance of ''Evans holes'' in the broad absorptions corresponding to combination transitions involving v 3 mode [9]. The Fermi resonance parameters, W RF = (4-7 cm À1 ), have similar values as the ''a'' parameters for RDD interactions.…”

“…The characteristic feature of the spectra is the large splitting value, Dm $ 20 cm À1 , of the triply degenerate m 3 vibration due to strong resonance dipole-dipole (RDD) interaction between the two interacting molecules. It has been shown [6,9] that the value of the splitting is determined by the RDD interaction parameter, a ¼ ðP 0 3 Þ 2 =ð2hcR 3 Þ, where P 0 3 is the dipole moment derivative of the monomer molecule with respect to the dimensionless normal coordinate Q 3 and R is the distance between centers of gravity of the dimer subunits. The large P 0 3 values of the interacting molecules (0.4-0.6 D) lead to large Dm splitting values.…”

“…[8,9]. The characteristic feature of the vibrational spectrum of CF 4 is the presence of the Fermi resonance for levels (v 1 , v 2 , v 3 + 1, v 4 ) and (v 1 , v 2 , v 3 , v 4 + 2) (where v 1 , v 2 , v 3 , v 4 = 0, 1, 2,. .…”