Electronic and geometric structures of various products of the scandium+ + water reaction

2001

Spectroscopic properties of novel aromatic metal clusters: NaM 4 ( M = Al,Ga,In ) and their cations and anions Gas phase infrared spectroscopy of mono-and divanadium oxide cluster cations Theoretical studies of the first-row transition metal phosphides J. Chem. Phys. 118, 9224 (2003); 10.1063/1.1568078The nature of metal-oxide chemical bond: Electronic structure of PdMgO and PdOMg moleculesThe equilibrium geometries, dissociation energies, and electronic structures of the ground and low-lying excited states for the first-row transition metal oxide cations, MO ϩ ͑MϭSc to Zn͒, have been studied using the multireference singles and doubles configuration interaction ͑MR-SDCI͒ and the multireference second-order Møller-Plesset methods. To investigate the applicability of the density functional theory ͑DFT͒ to an electronic structure system with a multiconfigurational character, the Becke exchange functional with the Lee-Yang-Parr correlation functional, the Becke exchange functional with the one-parameter progressive correlation functional ͑BOP͒, and the Becke three-parameter hybrid exchange functional with the Lee-Yang-Parr correlation functional ͑B3LYP͒ methods have also been applied. The DFT predicts the ground state M-O bond lengths in good agreement with the multireference-based methods except for MnO ϩ and CuO ϩ , which have a multiconfigurational electronic structure. With respect to the dissociation energies, the B3LYP results are in good agreement with the multireference-based methods, while the DFT with pure functionals overestimates the energetics by about 20 kcal/mol compared to the MR-SDCI method.

Section: Compoundmentioning

confidence: 99%

Theoretical study of first-row transition metal oxide cations

2001

“…[4][5][6][13][14][15][16][17][18][19][20][21][22][23][24][25][26] Armentrout and co-workers [8][9][10][11][12] have carried out a series of experiments, using a guided ion beam mass spectrometry, to investigate the catalytic activity of the respective transition metal cations. They investigated activation processes of methane, 8 ammonia, 9 and water molecules 10,11 by the firstrow transition metal cations, and discussed the similarity and differences of the reaction mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Theoretical study of the water activation by a cobalt cation: Ab initio multireference theory versus density functional theory

2001

Unimolecular decay of the thiomethoxy cation, CH 3 S + : A computational study on the detailed mechanistic aspects J. Chem. Phys. 111, 6759 (1999); 10.1063/1.480042Gas phase ion chemistry and ab initio theoretical study of phosphine. IThe reaction mechanism of Co ϩ ( 5 F, 3 F) with H 2 O has been studied by the ab initio multireference-based theory ͑MR-SDCI and MC-QDPT͒ and the density functional theory ͑B3LYP and BLYP͒. In the energetics derived by the MR-SDCI͑ϩQ͒ plus the B3LYP zero-point vibrational energy, the ion-dipole complex, CoOH 2 ϩ , is initially formed with the binding energy of 38.2 ͑triplet͒ and 34.1 ͑quintet͒ kcal/mol, which is the most stable complex in the respective potential energy surfaces. Then, Co ϩ activates one O-H bond of H 2 O, leading to the insertion complex, HCoOH ϩ . There are three possible dissociation channels from HCoOH ϩ , i.e., →CoOH ϩ ϩH, →CoH ϩ ϩOH, and →CoO ϩ ϩH 2 . The third dissociation is expected to occur through the transition state of a four-centered structure, with the activation barrier of 61.6 ͑triplet͒ and 49.2 ͑quintet͒ kcal/mol, although this dissociation has not been detected in the experiment. The ground state of CoO ϩ is predicted to be 5 ⌬, and the lowest triplet state is 3 ⌫ with the energy level of 20.8 kcal/mol above. The B3LYP provides the energetics qualitatively similar to the MR-SDCI͑ϩQ͒ ones through the reactions, with the maximum deviation of 13 kcal/mol. The calculated results are consistent with experimental observations.

“…31 Of course, these multireference methods require considerable computational costs, but recent progress has made it possible to apply those methods to molecular systems of moderate size routinely. [32][33][34][35][36] The number of theoretical studies on the reactions of the first-row transition metal ͑cation͒ plus elementary molecules is also growing, in which MR-SDCI, [37][38][39][40][41][42][43][44][45] MRMP ͑CASPT2͒, [45][46][47] or density-functional-theory ͑DFT͒ based methods [6][7][8][47][48][49][50][51][52][53] have been employed. Especially, there are increasing applications of the hybrid density functional B3LYP method, i.e., Becke's three parameter nonlocal hybrid exchange potential 54 with the nonlocal correlation functional of Lee, Yang, and Parr, 55 but its applicability to the transition state of the reaction has not been established yet ͑although it has been verified that B3LYP in most cases gives quite satisfactory results around the equilibrium struc-ture͒.…”

Section: Introductionmentioning

confidence: 99%

Theoretical study of ammonia activation by M+ (M=Sc, Ni, Cu)

1999

Articles you may be interested inAn all-electron density functional theory study of the structure and properties of the neutral and singly charged M 12 and M 13 clusters: M = Sc-Zn Probes of spin conservation in heavy metal reactions: Experimental and theoretical studies of the reactions of Re + with H 2 , D 2 , and HD Theoretical study of the water activation by a cobalt cation: Ab initio multireference theory versus density functional theoryThe reactions of the first-row transition metal cations, Sc ϩ ( 3 D, 1 D), Ni ϩ ( 2 D), Cu ϩ ( 1 S), with NH 3 have been studied by the multiconfigurational and multireference-based theories, to clarify the similarities and differences in the reactivity of early (Sc ϩ ) and late (Ni ϩ , Cu ϩ ) transition metal cations. In all the cases, the ion-dipole complex, MNH 3 ϩ , is initially formed with a C 3v symmetry structure, which is the most stable complex in the respective potential energy surfaces except for Sc ϩ ( 1 D). The M ϩ -NH 3 binding energy was evaluated as 42.4, 37.8, 50.9, and 48.1 kcal/mol for Sc ϩ ( 3 D), Sc ϩ ( 1 D), Ni ϩ , and Cu ϩ , respectively. In the second step, M ϩ is expected to activate one N-H bond of NH 3 , leading to the insertion complex, HMNH 2 ϩ . In Sc ϩ ( 3 D, 1 D), three different stationary points of HScNH 2 ϩ , i.e., C s ͑in-plane͒, C s ͑out-of-plane͒, and C 2v structures, were located, which correspond to a minimum point, a first-order saddle point, and a second-order saddle point, respectively. In these complexes, the singlet state originating from Sc ϩ ( 1 D) is largely stabilized compared to the triplets. The singlet HScNH 2 ϩ ͑in-plane͒ is calculated to be the most stable compound. There are three dissociation channels from HScNH 2 ϩ , i.e., →ScNH 2 ϩ ϩH, →ScH ϩ ϩNH 2 , and →ScNH ϩ ϩH 2 . The third dissociation occurs through the transition state of a four-centered structure, with a small activation barrier of 23 kcal/mol, in both singlet and triplet surfaces. As to the late transition metal cations Ni ϩ and Cu ϩ , there is no intermediate complex of HMNH 2 ϩ , thus, all the dissociations occur through highly vibrational excitations of MNH 3 ϩ . The calculated results are consistent with experimental observations.