W.W. Duley

Two-photon spectroscopy of thallium

Abstract The states n 2 P 0 1 2 , n 2 P 0 3 2 , and n 2 F 0 5 2 , 7 2 have been observed in Tl to n = 18, 21 and 26 respectively, using two photon laser spectroscopy and an ionization detector. An analysis of the quantum defects for these states and the spin-orbit splitting of the n 2 P 0 states is given.

Three-photon excitation of Rydberg series in lead and bismuth

Reports the observations of three-photon hybrid resonances and use this effect to investigate Rydberg states of lead and bismuth. In these experiments two-photon transitions occur in the molecular component of the vapour terminating on dissociative molecular states. Dissociation into one of several excited atomic states is followed by one-photon absorption to highly excited atomic Rydberg states. Even-parity Rydberg series have been observed in lead, and both even- and odd-parity Rydberg series have been observed in bismuth. The first ionisation limit of bismuth has been lowered by 3 cm-1 to 58762.0+or-0.3 cm-1.

Direct and hybrid two-photon transitions in Ga vapour

Abstract Dye laser spectroscopy of Ga vapor in an ion cell has lead to the identification of high lying n p 2 P o and n f 2 F o levels. A hybrid resonance involving the 5s 2 S 1 2 level has been observed together with resonant enhancement of members of the 4 2 P 0 3 4 → np 2 P 0 series due to thislevel.

Multiphoton excitation of visible and VUV luminescence in MgO crystals

Abstract Irradiation of pure MgO crystals with intense XeCl laser radiation yields VUV emission associated with the decay of bi-excitons. This emission exhibits a 4-photon dependence on incident laser intensity. Collisional excitation of luminescence from Cr 3+ and Ni 2+ impurities has been detected in doped samples. This emission also shows a multiphoton dependence on incident laser intensity.

Two-photon spectroscopy of ytterbium

Abstract Two-photon laser spectra of the Yb vapor have been obtained. Transitions to highly excited 4f 14 6s ns 1 S 0 and 4f 14 6s n d 1 D 2 states are seen in direct two-photon excitation. Hybrid resonances involving 4f 14 6s6p 1 P 0 1 and 4f 14 5d6s 3 D 2 intermediate states lead to transitions to 4f 14 6s ns 1 S 0 , 4f 14 6s n p 3 P 0 2,1 and 4f 14 6s n d 1 D 2 levels.

Collision broadening and shift of the sodium 3S-4D and 3S-5S lines by He, Ar and N2

Collision broadening and shift of the sodium 3S-4D and 3S-5S transitions by He, Ar and N2 has been measured using two-photon absorption and ion detection techniques. The perturber gas pressures ranged from 1 × 105N/m2 to 7 × 105 N/m2 (1–7 atmospheres) and it was found that the fwhm and shift varies linearly with pressure throughout this range. A comparison is made between our results and those of Biraben et al. who have used Doppler-free spectroscopy to study the effect of low pertuber pressures on the above transitions.

Narrow 3-photon autoionizing resonances in Tl and Yb

Abstract Narrow autoionizing resonances have been observed in Yb and Tl using direct 3-photon excitation of ground state atoms. The linewidth is 0.9 cm -1 in Yb and 0.4 cm -1 in Tl. Autoionizing levels in both atoms correspond to doubly excited electronic states. This is the first observation of such states in Tl.

Multiphoton ionization spectra in lithium vapour

Abstract The two-photon absorption spectrum to high-lying states of Li vapour has been obtained using ion-cell detection. 2 S states are observed to n = 32 and the 2 D series to n = 49. Simple heating techniques circumvented the problem of absorption by the blue-green band system of Li 2 which overlaps the series limit at 4600 A. The order of the ionization process was examined and found to vary as the square of the laser intensity for two-photon transitions. A conflict with data obtained with a space-charge-limited diode is examined and possible ionization mechanisms are discussed.

Impact broadening and shifts for 6sns 1S0 and 6snd 1D2 series of barium

Abstract Impact broadening and shifts of Ba transitions to parity forbidden Rydberg states have been measured using two-photon laser spectroscopy techniques. Broadening and shift rates for the 6s n s 1 S 0 (10 n n d 1 D 2 (8 n

Collision broadening and shift of the S and D rydberg levels of rubidium by He and Ar

Abstract The effects caused by collisional interactions of He and Ar on the high lying states of Rb are presented. Using both direct and hybrid two-photon excitation we report the broadening and shift of the Rb 5 2 S→ n 2 S(10⩽ n ⩽21) and 5 2 S → n 2 D (8⩽ n ⩽35) transitions. The perturber gas concentrations ranged from 0.40 relative density (r.d.) to 2.64 r.d. and the rate of broadening and shift has been calculated for the above transitions. When compared with previous results at much lower perturber concentrations our broadening and shift rates are similar for all n 2 S and 19 2 D levels except for the shift rate of the 19 2 D level. The broadening and shift of the hybrid series are found to be relatively unaffected by the participation of a real intermediate state.