Second hyperpolarizability of delta shaped disubstituted acetylene complexes of beryllium, magnesium, and calcium

Abstract

Present theoretical study involves the delta shape complexes of beryllium, magnesium, and calcium where the metal atom interacts perpendicularly with disubstituted acetylene. Most of the complexes are found to be fairly stable. The dependence of second-hyperpolarizability on the basis set with increasing polarization and diffuse functions has been examined which showed the importance of 'f-type' type polarization function for heavy metal (Mg, Ca) and 'd-type' polarization function for beryllium. Larger second hyperpolarizability has been predicted for complexes having significant ground state polarization and low lying excited states favoring strong electronic coupling. Transition energy plays the most significant role in modulating the second hyperpolarizability.

MgC6H2 Isomers: Potential Candidates for Laboratory and Radioastronomical Studies

“…The latter molecule has also been identified in the laboratory using Fourier transform microwave spectroscopy (FTMW) by McCarthy and Thaddeus in 2002 . While theoretical calculations on tetradehydrobenzenes (dibenzynes) have been done by various research groups, ,,− attempts to trap these molecules in low-temperature matrices have not yielded success yet although derivatives such as 3,6-difluoro-1,4-benzdiyne and 3,6-bis­(trifluoromethyl)-1,4-benzdiyne have been observed. ,, Identification of MgNC 3 and its metastable isomer MgCN 4 in IRC+10216 has triggered several theoretical and experimental studies on magnesium-bearing molecules, in particular, on their cyanopolyynes, , polyynes, − and other species. − The pure rotational spectrum of magnesium monoacetylide radical, MgC 2 H ( 2 Σ + ) has been recorded by Ziuyrs and co-workers in the laboratory using millimeter (mm)/submillimeter direct absorption spectroscopy in 1995. , These authors speculated the presence of MgC 2 H in space considering the fact that it is isoelectronic with both MgNC and MgCN, and is likely to be produced from HCCH , or CCH, as both are abundant molecules in the interstellar medium (ISM). In 2014, tentative assignments for MgC 2 H in IRC+10216 were given and in 2019 it was confirmed by Cernicharo and co-workers …”

Main-Group Metal Complexes of Benzene: Predicted Features of Stabilization and Isomerization

“…Among a huge multitude of such systems, intermolecular complexes of second-group metal atoms (mainly Be and Mg) were previously investigated from the viewpoint of nonlinear optical properties, such as hyperpolarizability [ 1 , 2 ], in relation to astrochemistry and radioastronomy [ 3 , 4 ], metal-containing heterocycles [ 5 ], intra- and intermolecular cooperativity of binding [ 6 ], and as potential units for a charge-governed structure manipulation [ 7 ]. In particular, one such very uncommon compound, diberyllocene (with a Be-Be bond), was produced in experiments very recently [ 8 ].…”