"vibrational spectroscopy" . "vibrational state" . "vibrational and rotational motion" . "vibration rotation" . "vibrational" . "symmetric top molecules" . "Rovibrational spectrum" . "rotational\u2013vibrational" . . . "Rotational\u2013vibrational spectroscopy" . . "Rotational\u2013vibrational spectroscopy" . "rotational quantum states" . "laser vibration-rotation-tunneling spectroscopy" . . .