A two‐state reactivity rationale for the reaction of ta atom with acetonitrile in the gas phase

Abstract

The spin-forbidden reaction mechanism of Ta ( 4 F, 5d 3 6s 2 ) with CH 3 CN, on two different potential surfaces (PESs) has been investigated at the B3LYP, MP2, and CCSD level of theory. Crossing points between the PESs are located using different methods, and possible spin inversion processes are discussed by means of spin-orbit coupling calculations. As a result, the reaction system will change its spin multiplicities near this crossing seam, leading to a significant decrease in the barrier of 2-4 TS3 from 24.17 to 5.36 kcal/mol, which makes the reaction access to a lower energy pathway and accelerate the reaction rate.

Rationalizing the Low‐Spin Products Observed for the Reactions M+CH3CN (M=V, Nb,Ta) Through a Non‐Spin Flip Scheme.

“…The present contribution, aims at rationalizing the viability of using a two step‐reaction scheme involving radical species to explain the above product distributions without invoking intersystem crossings between electronic states of different spin multiplicity, as it has been proposed in previous theoretical studies …”

“…Theoretically, different authors have modeled some of these matrix‐confined interactions through gas‐type simple reactions without taking into account explicitly the matrix effects . Instead, the ground state of the reactants and the lower‐spin products observed under matrix conditions are linked through a single pathway which emerges from the interaction between electronic states of different spin‐multiplicity (intersystem crossings) by using spin‐flip reactivity models, such as the two‐state or the multistate reactivity models .…”