Does the molecular structure of CaH_2 affect the dihydrogen bonding in CaH_2 HY(Y = CH_3,C_2H_3,C_2 H,CN,and NC) complexes? A quantum chemistry study using MP2 and B3LYP methods

Second-order Maller-Plesset （MP2） and density functional theory （DFT） calculations have been carried out in order to inves- tigate the structures and properties of dihydrogen-bonded CaH2...HY （Y = CH3, C2H3, C2H, CN, and NC） complexes. Our cal- culations revealed two possible structures for Call2 in CaH2..,HY complexes： linear （I） and bent （II）. The bond lengths, interac- tion energies, and strengths for H...H interactions obtained by both MP2 and B3LYP methods are quite close to each other. It was found that the interaction energy decreases with increasing electron density at the Ca-H bond critical point. At- om-in-molecule （AIM） results show that for all of Ca-H...H-Y interactions considered here, the Laplacian of the electron densi- ty at the H--.H bond critical point is positive, indicating the electrostatic nature of these Ca-H...H-Y dihydrogen bonded systems.

Second-order M ller-Plesset(MP2) and density functional theory(DFT) calculations have been carried out in order to investigate the structures and properties of dihydrogen-bonded CaH 2 HY(Y = CH 3,C 2 H 3,C 2 H,CN,and NC) complexes.Our calculations revealed two possible structures for CaH 2 in CaH 2 HY complexes:linear(I) and bent(II).The bond lengths,interaction energies,and strengths for H H interactions obtained by both MP2 and B3LYP methods are quite close to each other.It was found that the interaction energy decreases with increasing electron density at the Ca-H bond critical point.Atom-in-molecule(AIM) results show that for all of Ca-H H-Y interactions considered here,the Laplacian of the electron density at the H H bond critical point is positive,indicating the electrostatic nature of these Ca-H H-Y dihydrogen bonded systems.