Computational study of influence of diffuse basis functions on geometry optimization and spectroscopic properties of losartan potassium
PBN-AR
Instytucja
Instytut Fizyki Molekularnej Polskiej Akademii Nauk
Informacje podstawowe
Główny język publikacji
en
Czasopismo
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
ISSN
1386-1425
EISSN
Wydawca
PERGAMON-ELSEVIER SCIENCE LTD
DOI
URL
Rok publikacji
2015
Numer zeszytu
Strony od-do
1029-1038
Numer tomu
137
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Autorzy
(liczba autorów: 4)
Pozostali autorzy
+ 3
Streszczenia
Język
en
Treść
The work was aimed at investigating the influence of diffusion of basis functions on the geometry optimization of molecule of losartan in acidic and salt form. Spectroscopic properties of losartan potassium were also calculated and compared with experiment. Density functional theory method with various basis sets: 6-31G(d,p) and its diffused variations 6-31G(d,p)+ and 6-31G(d,p)++ was used. Application of diffuse basis functions in geometry optimization resulted in significant change of total molecule energy. Total molecule energy of losartan potassium decreased by 112.91 KJ/mol and 114.32 kJ/mol for 6-31G(d,p)+ and 6-31G(d,p)++ basis sets, respectively. Almost the same decrease was observed for losartan: 114.99 KJ/mol and 117.08 kJ/mol respectively for 6-31G(d,p)+ and 6-31G(d,p)++ basis sets. Further investigation showed significant difference within geometries of losartan potassium optimized with investigated basis sets. Application of diffused basis functions resulted in average 1.29 angstrom difference in relative position between corresponding atoms of three obtained geometries. Similar study taken on losartan resulted in only average 0.22 angstrom of dislocation. Extensive analysis of geometry changes in molecules obtained with diffused and non-diffuse basis functions was carried out in order to elucidate observed changes. The analysis was supported by electrostatic potential maps and calculation of natural atomic charges. UV, Fr-IR and Raman spectra of losartan potassium were calculated and compared with experimental results. No crucial differences between Raman spectra obtained with different basis sets were observed. However, Fr-IR spectra of geometry of losartan potassium optimized with 6-31G(d,p)++ basis set resulted in 40\% better correlation with experimental FT-IR spectra than FT-IR calculated with geometry optimized with 6-31G(d,p) basis set. Therefore, it is highly advisable to optimize geometry of molecules with ionic interactions using diffuse basis functions when accuracy of results is a priority. (C) 2014 Elsevier B.V. All rights reserved.
Cechy publikacji
ORIGINAL_ARTICLE
Inne
System-identifier
628306
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