Comparison of CBS-QB3, CBS-APNO, G2, and G3 thermochemical predictions with experiment for formation of ionic clusters of hydronium and hydroxide ions complexed with water

Abstract

The GAUSSIAN 2, GAUSSIAN 3, complete basis set-QB3, and complete basis set-APNO methods have been used to calculate DeltaH( composite function) and DeltaG( composite function) values for ionic clusters of hydronium and hydroxide ions complexed with water. Results for the clusters H3O+(H2O)n and OH-(H2O)n, where n=1-4 are reported in this paper, and compared against experimental values contained in the National Institutes of Standards and Technology (NIST) database. Agreement with experiment is excellent for the three ab initio methods for formation of these clusters. The high accuracy of these methods makes them reliable for calculating energetics for the formation of ionic clusters containing water. In addition this allows them to serve as a valuable check on the accuracy of experimental data reported in the NIST database, and makes them useful tools for addressing unresolved issues in atmospheric chemistry.

Observations of different core water cluster ions Y−(H2O)n (Y = O2, HOx, NOx, COx) and magic number in atmospheric pressure negative corona discharge mass spectrometry

“…[6,7] glow [52] and corona discharge ionizations [12,34] and liquid ionization [53] in water vapor, a discontinuous gap in the van't Hoff plot for H 3 O + (H 2 O) n (n = 0-6) between n = 3 and 4, [15 -17] and the complete symmetry of the H 3 O + (H 2 O) 3 core H 3 O + ion, obtained by the Eigen postulation, [54] ab initio molecular orbital calculations [18] and an experimental proof by noting enhancements of H 3 O + (TMA) 3 formed in mixed clusters with trimethylamine (TMA). [55] Eigen has postulated, furthermore, that a negative cluster ion HO − (H 2 O) 3 is the first hydrated shell with a C 3 symmetry, corresponding to the H 3 O + (H 2 O) 3 positive ion.…”

“…[55] Eigen has postulated, furthermore, that a negative cluster ion HO − (H 2 O) 3 is the first hydrated shell with a C 3 symmetry, corresponding to the H 3 O + (H 2 O) 3 positive ion. [54] The stability of HO − (H 2 O) n has been estimated by several methods such as the use of the van't Hoff plot for HO − (H 2 O) n (n = 0-7), [17,56] high-resolution vibrational spectroscopy of HO − (H 2 O) n (n = 1-5) [57] and ab initio calculations of H 0 and G 0 for HO − (H 2 O) n (n = 1-4) [18] and similar calculations for the structure of HO − (H 2 O) 3 . [18,57,58] The high intensity discontinuity at the HO − (H 2 O) 3 observed in our experimental system ( Fig.…”

“…[54] The stability of HO − (H 2 O) n has been estimated by several methods such as the use of the van't Hoff plot for HO − (H 2 O) n (n = 0-7), [17,56] high-resolution vibrational spectroscopy of HO − (H 2 O) n (n = 1-5) [57] and ab initio calculations of H 0 and G 0 for HO − (H 2 O) n (n = 1-4) [18] and similar calculations for the structure of HO − (H 2 O) 3 . [18,57,58] The high intensity discontinuity at the HO − (H 2 O) 3 observed in our experimental system ( Fig. 2 and Table 2) is the first direct mass spectrometric evidence for the specific high stability of HO − (H 2 O) 3 as the first hydrated shell as postulated by Eigen, [54] which was mentioned in our previous report.…”

Systematic testing of Gaussian and complete basis set methods with dispersion corrections for environmentally relevant clusters

“…Briefly, Gn theory is widely used as a composite theoretical method and has demonstrated to deliver accurate thermochemical data for a variety of environmentally relevant clusters [7][8][9][10]. CBS-x offers an alternative approach used to obtain accurate thermochemical data, and these methods are frequently applied to large chemical systems, E-mail address: kono@hku.hk including those with non-covalent interactions [11,12]. While Gn and CBS-x provide accurate energies for a wide range of noncovalently bound clusters, it is noteworthy, that G3 fails for a small group of clusters, such as (HF) 2 and (H 2 O) 2 , and these deviations arise primarily from method and basis set deficiencies in the G3 geometries and frequencies [13].…”

Comparação entre métodos compostos no cálculo de afinidades por próton e elétron em sistemas moleculares

“…[32][33][34][35][36][37][38][39][40][41][42][43][44] Outra aplicação interessante é no estudo do mecanismo em processos envolvidos em espectroscopia de massas. 45 A variedade de aplicações utilizando métodos compostos vem aumentando tanto em trabalhos teóricos como em trabalhos experimentais, devido à sua praticidade, confiabilidade e precisão em prever parâmetros físico-químicos.…”