a Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China; b Department of Physics, College of Science and Engineering, Qingdao University, Qingdao 266071, China
Abstract Density functional method (DFT) (B3p86) of Gaussian98 has been used to optimize the structure of the Tc$_2$ molecule. The result shows that the ground state for Tc$_2$ molecule is an 11-multiple state and its electronic configuration is $^{11}$Σ$_{\rm g}^-$, which shows the spin polarization effect of Tc$_2$ molecule of a transition metal element for the first time. Meanwhile, we have not found any spin pollution because the wavefunction of the ground state does not mingle with wavefunctions of higher energy states. So, that the ground state for Tc$_2$ molecule is an 11-multiple state is indicative of the spin polarization effect of Tc$_2$ molecule of a transition metal element: that is, there exist 10 parallel spin electrons. The non-conjugated electron is greatest in number. These electrons occupy different spacious tracks, so that the energy of Tc$_2$ molecule is minimized. It can be concluded that the effect of parallel spin of the Tc$_2$ molecule is larger than the effect of the conjugated molecule, which is obviously related to the effect of electron d delocalization. In addition, the Murrell--Sorbie potential functions with the parameters for the ground state $^{11}$Σ$_{\rm g}^-$ and other states of Tc$_2$ molecule are derived. Dissociation energy $D_{\rm e}$ for the ground state of $T_{\rm c2}$ molecule is 2.266eV, equilibrium bond length $R_{\rm e}$ is 0.2841nm, vibration frequency $\omega_{\rm e}$ is 178.52cm$^{-1}$. Its force constants $f_2$, $f_3$, and $f_4$ are 0.9200aJ$\cdot$nm$^{-2}$, --3.5700aJ$\cdot$nm$^{-3}$, 11.2748aJ$\cdot$nm$^{-4}$ respectively. The other spectroscopic data for the ground state of Tc$_2$ molecule $\omega_{\rm e}\chi_{\rm e}$, $B_{\rm e}$, $\alpha_{\rm e}$ are 0.5523cm$^{-1}$, 0.0426cm$^{-1}$, $1.6331\times10^{-4}$cm$^{-1}$ respectively.
Received: 18 May 2004
Revised: 23 August 2004
Accepted manuscript online:
Altmetric calculates a score based on the online attention an article receives. Each coloured thread in the circle represents a different type of online attention. The number in the centre is the Altmetric score. Social media and mainstream news media are the main sources that calculate the score. Reference managers such as Mendeley are also tracked but do not contribute to the score. Older articles often score higher because they have had more time to get noticed. To account for this, Altmetric has included the context data for other articles of a similar age.
