Basis set convergence study of the atomization energy, geometry, and anharmonic force field of SO2: The importance of inner polarization functions

1998 ◽  
Vol 108 (7) ◽  
pp. 2791-2800 ◽  
Author(s):  
Jan M. L. Martin
Keyword(s):  
Force Field ◽  
Basis Set ◽  
Atomization Energy ◽  
Set Convergence ◽  
Polarization Functions ◽  
Convergence Study ◽  
Anharmonic Force

Theoretical study of spectroscopic constants and anharmonic force field of formaldehyde

2014 ◽  
Vol 13 (06) ◽  
pp. 1450049 ◽  
Author(s):  
Xuejun Wang ◽  
Meishan Wang ◽  
Chuanlu Yang ◽  
Jing Li ◽  
Dianmin Tong
Keyword(s):  
Force Field ◽  
Theoretical Data ◽  
Dft Method ◽  
Force Constants ◽  
Coupling Constants ◽  
Basis Set ◽  
Basis Sets ◽  
Spectroscopic Constants ◽  
Equilibrium Geometries ◽  
Anharmonic Force

The equilibrium geometries of formaldehyde are optimized with B3LYP, B3PW91 and MP2 methods employing three basis sets 6-311++G(2d,2p), aug-cc-pVTZ and cc-pVTZ, respectively, which agree well with the corresponding experimental and previous theoretical data. The best optimized geometries are obtained at the theoretical level B3LYP/6-311++G(2d,2p) basis set. Basing on the calculated equilibrium geometries, the spectroscopic constants and anharmonic force field of H 2 CO are investigated. The results show that DFT method is superior to MP2 method at the calculation of spectroscopic constants and force constants of H 2 CO . The vibration–rotation interaction constants and fundamental vibrational wave numbers of H 2 CO are firstly theoretically calculated. The Coriolis coupling constants, cubic force constants and most of quartic force constants are firstly theoretically predicted.

Millimetre-wave and infrared spectroscopy of Br13 CN: anharmonic force field of cyanogen bromide from spectroscopic data and ab initio calculations

1997 ◽  
Vol 90 (3) ◽  
pp. 495-497
Author(s):  
CLAUDIO ESPOSTI ◽  
FILIPPO TAMASSIA ◽  
CRISTINA PUZZARINI ◽  
RICCARDO TARRONI ◽  
ZDENEK ZELINGER
Keyword(s):  
Infrared Spectroscopy ◽  
Force Field ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Spectroscopic Data ◽  
Cyanogen Bromide ◽  
Millimetre Wave ◽  
Anharmonic Force

Basis set dependence of SO stretching frequencies and its consequences for IR and VCD spectra predictions

2020 ◽  
Vol 22 (48) ◽  
pp. 27979-27986
Author(s):  
Kevin Scholten ◽  
Elric Engelage ◽  
Christian Merten
Keyword(s):  
Ir Spectra ◽  
Model Systems ◽  
Basis Set ◽  
Polarization Functions

Using chiral tosylates as model systems we evaluate the effect of diffuse and polarization functions on the quality of predicted VCD and IR spectra. Polarization functions on sulfur are shown to be important to reliable determine ACs using VCD.

Empirical anharmonic force field and equilibrium structure of hypochlorous acid, HOCl

1996 ◽  
Vol 259 (5-6) ◽  
pp. 614-618 ◽  
Author(s):  
R.M. Escribano ◽  
G. Di Lonardo ◽  
L. Fusina
Keyword(s):  
Force Field ◽  
Hypochlorous Acid ◽  
Equilibrium Structure ◽  
Anharmonic Force

Comparison of the Conformational Stability for Several Vinylhalomethanes and Silanes with Experiment Using MP2 Perturbation Theory and DFT

2007 ◽  
Vol 72 (1) ◽  
pp. 15-50 ◽  
Author(s):  
Wolfgang Förner ◽  
Hassan M. Badawi
Keyword(s):  
Experimental Data ◽  
Vibrational Spectra ◽  
Recent Literature ◽  
Conformational Stability ◽  
Basis Set ◽  
Major Conclusion ◽  
Stable Conformer ◽  
Polarization Functions ◽  
Complete Series ◽  
Triple Zeta

In recent literature it was reported that the valence triple zeta basis set augmented by polarization functions is not too reliable for vinyl monohalo- and dihalomethanes and -silanes, the halogen being fluorine and chlorine. The major conclusion was that a valence triple zeta basis is too small to be augmented by polarization functions in a balanced way, at least on vinylmonofluoromethane. Thus we decided to apply the 6-311++G** basis set to the complete series of methanes, silanes and germanes (the latter ones are just added for completeness because no experimental data are available for them and, moreover, we published them already previously) and to compare the results to experimental data available in the literature to see whether the failures of this basis set show up in the complete series of molecules. In the literature we found five such molecules and the information which of the conformers is the most stable. Indeed we found that predictions on the relative stability of conformers in those systems with this basis set and MP2 as well as DFT are with a 60:40 chance, three being correct predictions and two being incorrect ones out of the five. However, since the energy differences are rather small in these systems and due to the fact that - as a consequence of twofold degeneracy of the gauche conformer on the potential curve of the torsional vibration - the abundances of the conformers in equilibrium do not change too much, we decided to calculate also vibrational spectra for three examples and to compare them also to experiment. It is reported that besides the failures in total energy (we have chosen two examples where predictions of the nature of the stable conformer are correct, and one where it is not), the vibrational spectra are rather well reproduced, especially when experimental energies are used to calculate abundances in equilibrium in the case where the prediction of the stable conformer failed.

DFT anharmonic force field, and spectroscopic constants for phosphaethene, CH2PH

2017 ◽  
Vol 16 (3) ◽  
pp. 207-216 ◽  
Author(s):  
Wei-Xiu Pang ◽  
Hong-Ye Wu ◽  
Jian-Jun Zhao ◽  
Yi Lu ◽  
Yun-Bin Sun
Keyword(s):  
Force Field ◽  
Spectroscopic Constants ◽  
Anharmonic Force
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