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Isotopically pure 202 Hg vapor, contained in a quartz cell, was irradiated with the 2572.5 A output from a frequency-doubled Ar + laser, which produced Hg 2 A0 g ± excimer molecules by photoassociation followed by collisional relaxation. Simultaneously applied probe radiation from a ring laser, scanned over the range 4150–4650 A, gave rise to the H1 u ← A0 g + and H1 u ← A0 g − excitation spectra consisting of several hundred rotational components. Two previously unobserved rovibronic bands (one in each spectrum) were subjected to a rotational analysis which yielded spectroscopic constants that are compared with some previously reported values.

Isotopically pure 202Hg vapor, contained in a quartz cell, was irradiated with frequency-doubled 5140 A output from an Ar+ laser, which caused the formation of Hg2A0±g excimer molecules by photoassociation. Simultaneous probe radiation from a ring dye laser scanned over a range 5400–6000 A, produced the G0+u ← A0+g excitation spectrum which consists of several hundred well-resolved rotational components that have not been previously observed. Two vibronic bands were subjected to a rotational analysis which yielded spectroscopic constants that are compared with some previously reported values.

The doubly-excited 3Σ+u (4 3P, 4 3P) state of Zn2 was populated using pump and probe methods with time resolution. Structured excitation and fluorescence spectra were observed in the 300–330 nm region and are ascribed to 3Σ+u (4 3P, 4 3P)↔3Πg(4 3P) vibronic transitions, with partial resolution of the fine structure. An analysis of the spectra yielded the vibrational frequencies, relative energy, and relative equilibrium internuclear separations for the 3Σ+u and 3Πg states. The Zn2 excitation and fluorescence spectra contained a number of atomic lines whose origin was probed in a subsidiary experiment.

The 0 + u (4 1 P) state of Zn 2 was excited near the crossing of the 1 Σ + u (4 1 P) and 3 Π u (4 3 P) states, using pump and probe methods with time resolution. A structured excitation spectrum was observed in the 530–570 nm region and is ascribed to the 3 Π u (4 3 P)← 3 Π g (4 3 P) vibronic transitions. A fluorescence spectrum which was emitted in the 250–306 nm region is believed to arise from the 1 Σ + u →X 1 Σ + g bound—free decay. It consists of a “Condon internal diffraction pattern” whose profile suggests that it was emitted from a high vibrational level ( v ′ = 19) of the 1 Σ + u state.

The spectroscopy of the 3 Σ + g (4 3 P, 4 3 P) state in Zn 2 was studied by pump and probe methods with time resolution. Structured excitation and fluorescence spectra that were observed in the 266–277 nm region, are assigned as due to 3 Σ + g (4 3 P, 4 3 P) ↔ 3 Σ + u (4 3 P, 4 1 S) vibronic transitions. Vibrational analysis of the spectra yielded the vibrational frequencies, relative energies, and relative equilibrium internuclear separations for the two states.

The 3 Π u (4 3 P, 4 3 P) state of the Zn 2 excimer was excited by pump-and-probe irradiation of Zn vapor in a quartz cell. The resulting structured fluorescence and excitation spectra, which were recorded in the 270–290 nm spectral region, are interpreted as arising from 3 Π u (4 3 P, 4 3 P)↔ 3 Π g (4 3 P, 4 1 S) vibronic transitions. An analysis of the vibrational structures yielded the vibrational frequencies, relative energies, and relative equilibrium internuclear separations for the 3 Π u and 3 Π g states.

A structured excitation spectrum of Zn2 in the 420–470 nm region was registered in zinc vapor subjected to pump-and-probe excitation as the emitted bound—free fluorescence was monitored at 274 nm. The excitation and fluorescence spectra were interpreted as due to transitions involving the 1Σ+u (5 1S), 3Πg (4 3P), and X1Σ+g (4 1S0) states. An analysis of the vibrational structure yielded vibrational constants and relative energies for the 1Σ+u and 3Πg states.