Scaling of ab initio force fields by MOLVIB

Vibrational Spectra (FT-IR, FT-Raman and NMR) of 1, 5-Difluoro-2,4-dinitrobenzene based on Density Functional Calculations

“…Scaling of the force field was performed according to the SQM procedure [13,14] using selective scaling in the natural internal coordinate representation [15,16]. Transformation of the force field and subsequent normal coordinate analysis including the least square refinement of the scale factors, calculation of the potential energy distribution (PED) and the prediction of IR and Raman intensities were done on a PC with the Molvib program (version 7.0-G77) by Sundius [17,18]. For the graphs of simulated IR and Raman spectra, pure Lorentzian band shapes were used with a band width of 10 cm…”

A Comparative Study on the Structural and Vibrational Properties of Two Potential Antimicrobial and Anticancer Cyanopyridine Derivatives

“…The different interactions predicted for both derivatives in the two studied media were analyzed by means of calculations of the electronic charge density topological with the AIM200 program package [26]. The harmonic force fields for both derivatives were evaluated at the same level of theory by using the Molvib program [37] and following the SQMFF procedure [21]. To perform the complete assignments, only the potential energy distribution components (PEDs) ≥10% were considered from the resulting SQM.…”

“…The force constants were calculated from the corresponding scaled force fields by using the Molvib program [37], as was described in Section 2. A comparison of the principal force constants for both derivatives in the two studied media are given in Table 4.…”

Analysis of vibratinal spectra of 8-hydroxyquinoline and its 5,7-dichloro, 5,7-dibromo, 5,7-diiodo and 5,7-dinitro derivatives based on density functional theory calculations

“…Scaling of the force field was performed according to the SQM procedure [12,13] using selective scaling in the natural internal coordinate representation [14,15]. Transformations of the force field and subsequent normal coordinate analysis including the least square refinement of the scaling factors, calculation of potential energy distribution (PED) and the prediction of IR intensity were done on a PC with the MOLVIB program (version 7.0 -G77) written by Sundius [16,17]. For the plots of simulated IR, pure Lorentizian band shapes were used with a bandwidth (FWHM) of 6 cm −1 .…”