Rotational emission spectroscopy in ultra-dense hydrogen p(0) and pxDy(0): Groups pN, pD2, p2D and (pD)N

The rotational emission spectrum induced in ultra-dense deuterium D(0) by a 1064 nm pulsed Nd:YAG laser with 0.4 J pulses was recently reported (J. Mol. Struct. 1130 (2017) 829-836). Good agreement between theory and experiment was found. The bond distances were determined for spin levels s = 2, 3 and 4 with a precision as good as ± 0.003 pm. The existence of these rotational lines supports the strongly bound cluster model of D(0). The similar spectra are now studied for ultra-dense protium p(0) and for the ultra-dense hydrogen mixture pxDy(0), giving several lines different from D(0). A rich spectrum of emission lines from pN and (pD)N groups in the chain clusters H2N(0) is observed and partially assigned. The observation of unique lines gives evidence for rotations in groups pN, pD (identified previously), pD2, p2D and (pD)2 in the long chain-clusters, complementing the previously identified pD and DN groups. Three-atomic and four-atomic clusters are of great interest, since the nuclear processes studied in several publications take place in such clusters. Emission lines from three-atomic planar groups pD2(0) and p2D(0), either in the chain clusters or as free clusters, are observed. Coupling of the dipole antennas (pD)N to neighboring parts of the homopolar chain-clusters H2N(0) probably gives several weaker lines. No certain evidence of free symmetric or asymmetric H4(0) tops like pD3(0) and p2D2(0) is found. Such strongly bound H4(0) molecules were studied by TOF-MS previously and they have slightly shorter bond distances which makes their final identification more difficult.