Anharmonic cubic force field of methane

Abstract

Anharmonic K,,, parameters of the CH, molecule potential function are derived from the experimental rotational, tetrahedral splitting and resonance parameters of CH, and CH,D,. As an illustration of the correctness of the potential parameters obtained, the original spectroscopic constants of CH, and CH2D, are theoretically reproduced.Calculations of the spectroscopic constants of CH,D and CHD3 molecules are also given for illustrations.

Simultaneous Determination of Force Constants and Dipole Moment Derivatives of Methane

“…They are written as follows: * They are calculated from the correspondence relations between the notations for our force constants and those used in Refs. (8) and (10). [26] where is the reduced mass…”

“…Similarly, it is seen from Eq. [10] that the cubic dimensionless normals force constants depend, in addition to the aforementioned constants, on the cubic symmetric force con- …”

“…Hirota (6) has obtained 13 cubic internal force constants. In two studies (8,10), Makushkin and coworkers have determined all 13 cubic normal force constants. Gray et al (7) have extracted all five quadratic symmetric force constants and six cubic ones.…”

The High-Resolution Fourier Transform Spectrum of Dideuterated Methane CH2D2in the Region between 1900 and 2400 cm−1

“…As shown in Table 9, the three values do not d Ref. (13). e Values in parentheses denote experimental errors.…”

On the “expanded local mode” approach applied to the methane molecule

“…In our case, we estimated the value of the sin c parameter from analysis of (a) relations between the harmonic frequencies, x k , of the CH 4 , [6,18], CH 2 D 2 , [7], and CH 3 D; CHD 3 , [10], isotopic species, and (b) experimental values of Coriolis coefficients from Ref. [19].…”