Search

The dissociation energy of the ground state of NaH was determined by analyzing the observed near dissociation rovibrational levels. These levels were reached by stimulated emission pumping and fluorescence depletion spectroscopy. A total of 114 rovibrational levels in the ranges 9≤v″≤21 and 1≤J″≤14 were assigned to the X 1Σ+ state of NaH. The highest vibrational level observed was only about 40 cm-1 from the dissociation limit in the ground state. One quasibound state, above the dissociation limit and confined by the centrifugal barrier, was observed. Determining the vibrational quantum number at dissociation vD from the highest four vibrational levels yielded the dissociation energy De=15 815±5 cm-1. Based on new observations and available data, a set of Dunham coefficients and the rotationless Rydberg–Klein–Rees curve were constructed. The effective potential curve and the quasibound states were discussed. [ABSTRACT FROM AUTHOR]

The phenomenon of electronic orbital angular momentum L uncoupled from its internuclear axis has been observed in the sodium dimer using high-resolution cw optical-optical double-resonance spectroscopy. When L uncoupling occurs, the degeneracy of Λ doubling is removed. In our experiment, the intermediate B 1Πu state of Na2 is excited from the thermally populated ground X 1Σg+ state by a single-line Ar+ laser. Then, a single-mode dye laser is used to probe the Rydberg states from the intermediate state. The signals are detected by monitoring the UV fluorescence from the triplet gerade states back to the a 3Σu+ state via collision energy transfer. Under our experimental resolution, the splitting of Λ doubling in the 5 1Δg state of Na2 can be measured. A total of 136 rovibronic levels with e/f parities have been assigned to the 5 1Δg state. The Λ-splitting constants deduced from these data are q0=0.376(90)×10-4 cm-1, qv=0.114(6)×10-4 cm-1, and μ=0.76(33)×10-8 cm-1. In general, the Λ splitting of the Δ states is considerably smaller than that of the Π states. However, the first-order splitting constants q0 and qv reported here are larger than those in the B 1Πu state. This is due to the L uncoupling of the Rydberg states. [ABSTRACT FROM AUTHOR]

The phenomenon of electronic orbital angular momentum L uncoupled from its internuclear axis has been observed in the sodium dimer using high-resolution cw optical-optical double-resonance spectroscopy. When L uncoupling occurs, the degeneracy of Λ doubling is removed. In our experiment, the intermediate B 1Πu state of Na2 is excited from the thermally populated ground X 1Σg+ state by a single-line Ar+ laser. Then, a single-mode dye laser is used to probe the Rydberg states from the intermediate state. The signals are detected by monitoring the UV fluorescence from the triplet gerade states back to the a 3Σu+ state via collision energy transfer. Under our experimental resolution, the splitting of Λ doubling in the 5 1Δg state of Na2 can be measured. A total of 136 rovibronic levels with e/f parities have been assigned to the 5 1Δg state. The Λ-splitting constants deduced from these data are q0=0.376(90)×10-4 cm-1, qv=0.114(6)×10-4 cm-1, and μ=0.76(33)×10-8 cm-1. In general, the Λ splitting of the Δ states is considerably smaller than that of the Π states. However, the first-order splitting constants q0 and qv reported here are larger than those in the B 1Πu state. This is due to the L uncoupling of the Rydberg states. [ABSTRACT FROM AUTHOR]

The doubly excited valence (3p+3p) 2 1Δg state of Na2 is experimentally observed by using optical-optical double resonance spectroscopy. A single line Ar+ laser (a total of nine lines) was used to pump the sodium dimers from thermally populated ground state X 1Σg+ to the intermediate B 1Πu state. Then, a single mode Ti:sapphire laser was used to probe the doubly excited 2 1Δg state. Violet fluorescence emitted from the highly excited states (mainly 2 3Πg or 3 3Πg states which are transferred from 2 1Δg state via collision) to the a 3Σu+ state was monitored by a filtered photomultiplier tube (PMT). A total of 582 rovibrational levels of 2 1Δg state were observed, identified, and assigned to the vibrational and rotational quantum numbers in the range of 0≤v≤28 and 11≤J≤99, respectively. The absolute vibrational quantum number assignment was verified by comparing the totally resolved fluorescence with the calculated Franck-Condon factors between 2 1Δg state and B 1Πu state. Dunham coefficients and Rydberg-Klein-Rees potential curve were derived from these observed quantum levels. The primary molecular constants of Na2 2 1Δg state are Te=32 416.759(15) cm-1, ωe=124.8484(36) cm-1, Be=0.119 158(3) cm-1, and Re=3.508 20(5) Å. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Reports on the theory and analysis of sodium dimmer Rydberg states observed by all-optical triple resonance (AOTR) spectroscopy. Long-range potential theory (LRPT) in Hund's case; Analysis of the AOR data; Calculation of theoretical quantum defects for the series in Hund's case.

The doubly excited valence (3p+3p) 2 1Δg state of Na2 is experimentally observed by using optical-optical double resonance spectroscopy. A single line Ar+ laser (a total of nine lines) was used to pump the sodium dimers from thermally populated ground state X 1Σg+ to the intermediate B 1Πu state. Then, a single mode Ti:sapphire laser was used to probe the doubly excited 2 1Δg state. Violet fluorescence emitted from the highly excited states (mainly 2 3Πg or 3 3Πg states which are transferred from 2 1Δg state via collision) to the a 3Σu+ state was monitored by a filtered photomultiplier tube (PMT). A total of 582 rovibrational levels of 2 1Δg state were observed, identified, and assigned to the vibrational and rotational quantum numbers in the range of 0≤v≤28 and 11≤J≤99, respectively. The absolute vibrational quantum number assignment was verified by comparing the totally resolved fluorescence with the calculated Franck-Condon factors between 2 1Δg state and B 1Πu state. Dunham coefficients and Rydberg-Klein-Rees potential curve were derived from these observed quantum levels. The primary molecular constants of Na2 2 1Δg state are Te=32 416.759(15) cm-1, ωe=124.8484(36) cm-1, Be=0.119 158(3) cm-1, and Re=3.508 20(5) Å. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]