Dispersed fluorescence spectroscopy of jet-cooled AgAu and Pt2

Abstract

Dispersed fluorescence spectroscopy has been used to study jet-cooled AgAu and Pt 2. Fluorescence resulting from the excitation of five bands of the A←X 1 ⌺ ϩ system of AgAu was dispersed, and 51 measured ground state vibrational levels were fit to provide ground state vibrational constants of e Љϭ198.22Ϯ0.11 cm Ϫ1 and e Љx e Љϭ0.512Ϯ0.002 cm Ϫ1. A Franck-Condon calculation was performed using the experimental values of the ground and excited state vibrational frequencies and anharmonicities, providing an estimate of the change in bond length upon excitation of the A←X system of ⌬r e ϭ0.214Ϯ0.005 Å. Fluorescence resulting from four different excitations of Pt 2 was dispersed, providing vibrational constants for the ground and two low-lying excited states. Ground state vibrational constants of e ϭ222.3 cm Ϫ1 and e x e ϭ0.62 cm Ϫ1 were obtained, based on the analysis of 16 measured ground state vibrational levels. In addition, a low-lying excited state was located at T 0 ϭ2877 cm Ϫ1 , with e ϭ197 cm Ϫ1. This state perturbed the ground state, from which it was deduced that it has the same symmetry as the ground state. A comparison to theoretical calculations suggests that both states have 0 g ϩ symmetry. Finally, a metastable state of Pt 2 lying at an unknown energy was determined to have e ϭ211 cm Ϫ1 , e x e ϭ0.4 cm Ϫ1 .

Does spin–orbit coupling effect favor planar structures for small platinum clusters?

“…Both of these calculated excitation energies are much better than the ones obtained by Fortunelli in 1999 [19]. [27].…”

Chemical State of Adsorbed Sulfur on Pt Nanoparticles

“…[39] The experimental value of the S 2 equilibrium bond length [40] of 188.9 pm is within 2.5 % of the calculated value of 193.5 pm. The experimental vibrational frequency [40] of 725.7 cm À1 is about 3.4 % larger than the calculated value of 701.6 cm…”

Calculation of the Spectroscopic Constants and Strength of the Electron Transition A0+-X 1Σ+ of the AgAu Molecule

“…Comparison between the predicted and experimental vibrational, rotational, and centrifugal constants has proved the high accuracy of the method of calculation of molecular constants. In the present work, the spectroscopic constants are calculated for the ground (X 1 Σ + ) and excited (A0 + ) electronic states of the AgAu molecule, the characteristic feature of which is a more complex structure of the spectrum in comparison with the earlier considered biatomic heteronuclear molecules [6,7], which is due to the higher density of the electronic, vibrational, and rotational energy levels.Investigations of the spectrum of the A0 + -X 1 Σ + transition of 107 Ag 197 Au by various laser methods, the technique of supersonic molecular beams, and selective mass spectrometry were carried out in [8,9]. Only vibrational constants for combining states were determined.…”

“…Investigations of the spectrum of the A0 + -X 1 Σ + transition of 107 Ag 197 Au by various laser methods, the technique of supersonic molecular beams, and selective mass spectrometry were carried out in [8,9]. Only vibrational constants for combining states were determined.…”

“…Preliminary calculations of the values of r e by the additivity rule for the ground states of CuAg and CuAu gave quite satisfactory results that differed from the experimental ones by 0.04 and 0.70%, respectively. In [9], the difference between the equilibrium internuclear distances of the excited and ground states ∆r e = 0.214 ± 0.005 A° was determined by analyzing the distribution of the intensities of the electronic vibrational bands in the spectrum of the laser induced fluorescence of the A → X transition of AgAu. Applying this value and the value of ∆r e (X 1 Σ + ), the equilibrium internuclear distance was determined for the excited state r e (A) = 2.715 A°.…”