Near infrared laser spectroscopy of solid parahydrogen: The crystal-field splitting of rovibrational W1(0) transition

The fine structure of the rovibrational W1(0) transition (v = 1 ← 0, J = 6 ← 0) of solid parahydrogen has been observed using high-resolution near infrared diode laser spectroscopy. Similar to the case of the pure rotational W0(0) transition, the W1(0) transition also exhibits triplet structure which is interpreted as the crystal-field split M components of the J = 6 manifold. The observed splitting is consistent with the theoretical prediction based on the localized J = 6 rotons. The crystal-field splitting parameters obtained by least-squares fitting are in good agreement with the previous work on W0(0) transition.