The Cluster Fe&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;Si&amp;lt;sub&amp;gt;18&amp;lt;/sub&amp;gt; as the New Quantum Bit System

K V Simon,A V Tulub

doi:10.4236/cc.2015.32004

Abstract

Multiconfiguration quantum chemical calculation of geometry and electron properties of Fe2Si18 cluster indicates on the predictable change of spin states as a function of the excitation energy beginning from ground state with the total spin S = 4. The charges on the two Fe atoms are quite different as well as the charge distribution on the surrounding Si atoms. Nevertheless the total dipole moment of the cluster is a monotonically decreasing function of the excitation energy and it reaches practically zero value in the first singlet state in which the cluster represents a new version of a quibit system.

Highlights

Some number of bi-center clusters of the T2Sin type were primarily studied for the transition metals (T = Cr, Mn) [1] and for the transition metals T = Fe, Co, Ni [2], with a number n in the range 1 ≤ n ≤ 8 by the density functional theory (DFT) in the PBE approach
The geometry of small Fe2Sin is characterized by large number of local minima what prevents the predictable change of different spin states with the increasing of excitation energy of a system
Tulub containing the transition elements, the Fe-atom especially, see in this connection the table 6 in [3] where some number of DFT methods are compared with configuration interaction (CI) approach for the case of FeSi4 cluster

Summary

Introduction

The later can be achieved in the case of Fe2Si18 cluster, which electronic properties are investigated below in a framework of multireference configuration interaction approach with the singlet and double replacements into the external space. The DFT methods are not suitable enough for obtaining the correct sequence of exited states and especially for the description of a singlet state in the systems. (2015) The Cluster Fe2Si18 as the New Quantum Bit System. V. Tulub containing the transition elements, the Fe-atom especially, see in this connection the table 6 in [3] where some number of DFT methods are compared with configuration interaction (CI) approach for the case of FeSi4 cluster. The search of the two-state systems represents intriguing story in the modern investigations of a quantum computer systems. The singlet state of Fe2Si18 cluster would have a special interest in this connection

Calculation Procedure

Conclusions