Spectroscopy of A 30(+)<--X 10(+) and B 31<--X 10(+) transitions in CdNe and CdAr molecules

The structure of the lowest electronic Rydberg state of CdAr complex determined by laser double resonance method in a supersonic jet-expansion beam

The lowest E1(3Sigma(+)) Rydberg state of the CdAr van der Waals (vdW) complex was investigated by means of an optical-optical double resonance (OODR) method of laser spectroscopy in conjunction with a free jet-expansion molecular beam. Two dye lasers were employed for the two-step excitation. The A0(+)(3Pi(+)) and B1(3Sigma(+)) states were used as intermediates in the excitation process from the X0(+)(1Sigma(+)) ground state. Two types of bound-bound excitation spectra of the E1<--A0(+) and E1<--B1 transitions were recorded indicating the existence of two, well defined minima in the E1-state potential energy (PE) curve. First, considerably deep, with the well depth of D(e)'(E1(2))=1309.0 cm(-1) and second, separated by a positive PE barrier, with D(e)'(E1(2))=24.2 cm(-1). Combination of bound-bound and first-time observed bound-free excitation spectra enabled a complete determination of the spectroscopical parameters of the PE curve of the E1-Rydberg state, the height of the PE barrier and its approximate location. In the excitation spectra of the E1<--B1 transition, a nodal structure of the bound-free transitions was observed and elucidated by a projection of the B1-state vibrational wave-functions onto the E1-state potential barrier and/or onto the repulsive part of the E1-state PE curve. The experimental results of our investigation coincides well with recently published results of ab initio calculation of Czuchaj and co-workers [Chem. Phys. 248 (1999) 1; Chem Phys. 263 (2001) 7; Theor. Chem Acc. 105 (2001) 219].

Interatomic potentials of cadmium-argon B1(3sigma+) and X0+(1sigma+) states based on near-dissociation expansion and 'hot' bands observed in the B1 <-- X0+ excitation spectrum

B1(3sigma+) <-- X0+(1sigma+) excitation spectrum of the cadmium-argon van der Waals molecule has been recorded in the experiment of a continuous supersonic molecular beam crossed with a pulsed dye laser beam. The B1-state dissociation energy was directly observed and a long-range behavior of the B1-state intermolecular potential was derived using a near-dissociation expansion procedure of LeRoy and Bernstein. A first-time direct determination of the X0+ ground state characteristics based on 'hot' bands observed is presented as well. The new result is compared with other experimental and theoretical reports available in the literature.