
Theoretical investigations of spectroscopic parameters and molecular constants for electronic ground state of Cl_{2} and its isotopes
Shi DeHeng, Zhang XiaoNiu, Liu Hui, Zhu ZunLue, Sun JinFeng
Chin. Phys. B, 2010, 19 (10):
103401.
DOI: 10.1088/16741056/19/10/103401
The potential energy curve of the Cl_{2}(X^{1}Σ_{g}^{+}) is investigated by the highly accurate valence internally contracted multireference configuration interaction (MRCI) approach in combination with the largest correlationconsistent basis set, augccpV6Z, in the valence range. The theoretical spectroscopic parameters and the molecular constants of three isotopes, ^{35}Cl_{2}, ^{35}Cl^{37}Cl^{ } and ^{ 37}Cl_{2}, are studied. For the ^{35}Cl_{2}(X^{1}Σ_{g}^{+}), the values of D_{0}, D_{e}, R_{e}, ω_{e}, ω_{e}χ_{e}, α_{e} and B_{e} are obtained to be 2.3921 eV, 2.4264 eV, 0.19939 nm, 555.13 cm^{1}, 2.6772 cm^{1}, 0.001481 cm^{1} and 0.24225 cm^{1}, respectively. For the ^{35}Cl^{37}Cl(X^{1}Σ_{g}^{+}), the values of D_{0}, D_{e}, R_{e}, ω_{e}, ω_{e}χ_{e}, α_{e} and B_{e} are calculated to be 2.3918 eV, 2.4257 eV, 0.19939 nm, 547.68 cm^{1}, 2.6234 cm^{1}, 0.00140 cm^{1} and 0.23572 cm^{1}, respectively. And for the ^{37}Cl_{2}(X^{1}Σ_{g}^{+}), the values of D_{0}, D_{e}, R_{e}, ω_{e}, ω_{e}χ_{e}, α_{e} and B_{e} are obtained to be 2.3923 eV, 2.4257 eV, 0.19939 nm, 540.06 cm^{1}, 2.5556 cm^{1}, 0.00139 cm^{1} and 0.22919 cm^{1}, respectively. These spectroscopic results are in good agreement with the available experimental data. With the potential of Cl_{2} molecule determined at the MRCI/augccpV6Z level of theory, the total of 59 vibrational states is predicted for each isotope when the rotational quantum number J equals zero (J = 0). The theoretical vibrational levels, classical turning points, inertial rotation and centrifugal distortion constants are determined when J = 0, which are in excellent accordance with the available experimental findings.
