Absorption and Luminescence Spectra of Titanium Atoms Isolated in Noble Gas Matrices

The absorption spectra of titanium atoms, isolated in argon or xenon matrices, have been measured at low temperatures. The spectra consist of a large number of bands in the visible and near‐uv regions, which are correlated with transitions of gaseous neutral titanium atoms. Oscillator strengths are obtained for the absorption bands of isolated titanium, and these values are compared to intensity data on the gaseous spectrum. In an argon, but not in a xenon matrix, upon excitation with appropriate uv light, the metal atoms yield a relatively intense luminescence spectrum consisting of two bands. One, occurring in the 16–16 600 cm⁻¹ region, is assigned to the $z^5{G}^0{\mathrm{\hspace{0.17em}\to \hspace{0.17em}a}}^{3}F$ transition. The origin of the second band system, occurring at 14–15 000 cm⁻¹, is uncertain. The matrix shifts are found to depend on the transition energy, increasing in argon but decreasing with energy in xenon matrices. These results provide new data for testing current theories of matrix shifts.