Predissociation of the A 2Sigma+, C 2Sigma+ and D 2Sigma+ levels of 4HeH from a multistate close-coupling scattering approach

We have implemented a multistate close-coupling scattering approach to the calculation of the positions and partial and total widths of the rovibrational levels of the 2Sigma+ states of the 4HeH excimer molecule. Good agreement with available experimental data is obtained while a number of predictions are made. The results of the present multistate approach (MSA) are compared to those of the two-state approach (TSA), previously applied by a number of methods. Only for the lowest bound excited state, the A 2Sigma+, is there agreement, signifying the dominance of the A-X 2Sigma+ interaction. For the higher lying C and D 2Sigma+ states, the MSA produces significantly different results. The same should apply to similar situations in other excimer spectra.