DFT and CIS(D) theoretical study on the ground and excited states of pentanitrogen cation

Abstract

Different isomers of N 5 + were modeled at DFT(PBE0)/aug-cc-pV(Q + d)Z, and their ground(transition) state characteristics were assessed through frequency calculations. Single-point energies were accomplished at PBE0/aug-cc-pV(5 + d)Z. Nonlinear optical susceptibilities (NLO) of isomers were accomplished using Firefly, while the linear optical invariant was examined using the finite-field method, Firefly, and modified dipole field tensor in the presence of two different screening factors. The excited states, singlets and triplets, of N 5 + 1 P + g were modeled at the CIS and CIS(D) and then their optical parameters were estimated at TDFT(PBE0)/aug-cc-pV(Q + d)Z using Firefly. The singlet N 5 + 1 P + g is found the most stable isomer, with the inversional rate constant larger than that of the Cs isomer and high energy barrier with the triplet counterpart. Isomers 2, 3, and 4 are found local minima, while 5 and 6 are saddle points: transition states between equivalent invertomers. Energy calculations of the singlet and triplet isomers were in excellent agreement with the literature. An excellent correlation is found between the average polarizability and the impulse factor. Substantial variations were found between the singlet and triplet excited states in terms of energy, geometry, and optical properties from one side and with N 5 + 1 P + g from the other side. Reactivity indices showed that N1 and N5 are the optimum nucleophilic and electrophilic reactivity sites.

Synthesis, identification, density functional and Hirshfeld surface studies of 2,2′‐disulfanediylbis(tetrahydro‐4H‐cyclopenta[d][1,3,2]dioxaphosphole‐2‐sulfide)

“…Recently and according to the great progress in the supercomputers, quantum chemical methods become very useful tools in determining the molecular structures, electronic structure andreactivity of the molecules. The conceptual density functional theory (DFT) as one of the quantum chemical methods has been effectively used to compare the experimental data with the theoretical ones 25–27 …”