Predissociation of the b^3Пg （v=9） State of He2 Excimer

The predissociation of the v=9 level in the b^3Пg state by the 3∑u^＋ state of helium eximer （He2） was studied based on the newly observed （9, 3） band in the b^3Пg （v=9） system in the region of 12065-12445 cm^-1 employing optical heterodyne-concentration modulation absorption spectroscopy. With the help of the previous potential energy curves and molecular constants of He2, the corresponding predissociation mechanism for the b^3Пg （v=9） state was analyzed. An RKR potential energy curve of b^3Пg and an ab initio potential curve of 3∑g^＋ were used to calculate the predissociation linewidths that show basic agreement with observations, which can quantitatively explain the experiments.

A1∑＋ State Lifetime and Predissociation of Cull

A combined cavity ringdown （CRD） and laser induced fluorescence （LIF） spectroscopic study on the A1∑＋-X1∑＋ transition of Cull has been presented. The Cull molecule, as well as its deuterated isotopologue CuD, are produced in a supersonic jet expansion by discharging H2 （or D2） and Ar gas mixtures using two copper needles. Different profiles of relative line intensities are observed between the measured LIF and CRD spectra, providing an experimental evidence for the predissociation behavior in the A1∑＋ state of Cull. The lifetimes of individual upper rotational levels are measured by LIF, in which the J＇-dependent predisso- ciation rates are obtained. Based on the previous theoretical calculations, a predissociation mechanism is concluded due to the strong spin-orbit coupling between the A1∑＋ state and the lowest-lying triplet 3∑＋ state, and a tunneling effect may also be involved in the predis- sociation. Similar experiments are also performed for CuD, showing that the A1∑＋ state of CuD does not undergo a predissociation process.

Three-dimensional quantum dynamics study of vibrational predissociation of HeI_2 van der Waals molecule for low vibrational excitation using the time-dependent wave packet method

Three-dimensional quantum mechanical calculations for vibrational predissociation of HeI2(B) van der Waals molecules are presented using the time-dependent wave packet technique within the golden rule approxima tion.The total and partial decay widths,lifetimes,rates and their dependence on initial vibrational states were obtained for HeI2 at low initial vibrational excited levels.Our calculations show that the calculated tota decay widths,lifetimes and rates agree well with those extrapolated from experimental data available The predicted total decay widths as a function of initial vibrational states exhibit highly nonlinear behavior.The very short propagation time (less.than 1 ps) required in the golden rule wave packet calculation is determined by the duration time of the final state inter-action between the fragments on the vibrationally deexcited adiabatic potential surface.The final state interaction between the fragments is shown to play an important role in determining the final rotational distribution This interpreta tion clearly explains the dynamical effect that the final rotational distribution shifts to the lower rotational energy levels as the initial vibrational quantum number v increases.

Controlling Population Transfer and Dissociation Rate of Na2 Molecules with Ultra-Short Intense Laser Pulses

A scheme used for controlling the population transfer and the dissociation rate of Na2 molecules is described by using the quantum wavepacket dynamical method. It is theoretically shown that the population transfer and the dissociation rate of Na2 molecules can be controlled by pump and probe laser pulses with appropriate widths of pulses, sequence and intensities.

Determination of Scaling Parameter and Dynamical Resonances in Complex-Rotated Hamiltonian Ⅱ: Numerical Analysis

This paper is concerned with the determination of a unique scaling parameter in complex scaling analysis and with accurate calculation of dynamics resonances. In the preceding paper we have presented a theoretical analysis and provided a formalism for dynamical resonance calculations. In this paper we present accurate numerical results for two non-trivial dynamical processes, namely, models of diatomic molecular predissociation and of barrier potential scattering for resonances. The results presented in this paper confirm our theoretical analysis, remove a theoretical ambiguity on determination of the complex scaling parameter, and provide an improved understanding for dynamical resonance calculations in rigged Hilbert space.

Time-dependent treatment of intramolecular energy transfer for HeICl complex

The time-dependent golden wave packet method has been used for calculating the decay widths of vibrational predissociation for HeICl complex in the B state with total angular momentum J=0. This is a good example of intramolecular energy transfer, We examine the dependence of the final rotational distribution (partial decay width) of ICI fragment an the stretching excitation. It is found that computed final rotational distributions are weakly dependent on the vibrational level being excited. Unlike the smoothly varying rotational distribution for lower initial vibrational levels, for higher initial vibrational levels the rotational distribution indicates the very pronounced oscillatory structure. The analysis of the rotational distribution as a function of propagation time reveals the predominant role of the final states interaction in determining the final rotational distribution.