Infrared spectra of seeded hydrogen clusters:(para-H_2)_N-N_2O and (ortho-H_2)_N-N_2O,N=2-13

摘要

High-resolution infrared spectra of clusters containing para-H_2 and/or ortho-H_2 and a single nitrous oxide molecule are studied in the 2225-cm~(-1) region of the v_l fundamental band of N_2O.The clusters are formed in pulsed supersonic jet expansions from a cooled nozzle and probed using a tunable infrared diode laser spectrometer.The simple symmetric rotor-type spectra generally show no resolved K structure,with prominent Q-branch features for ortho-H_2 but not para-H_2 clusters.The observed vibrational shifts and rotational constants are reported.There is no obvious indication of superfluid effects for para-H_2 clusters up to N=13.Sharp transitions due to even larger clusters are observed,but no definite assignments are possible.Mixed (para-H_2)_N-(ortho-H_2)_M-N_2O cluster line positions can be well predicted by linear interpolation between the corresponding transitions of the pure clusters.