Although the foundations of quantum mechanics were laid down by Planck and Einstein at the beginning of 20th century, there are still many details of quantum effects that are not yet fully explored and understood. Even if we do not always think about them, they (e.g., H atom tunneling) influence everyday life via chemical and even biological processes. Quantum chemistry now is a working horse in many fields in chemistry, from structural chemistry, designing and understanding reactions, to drug research. Quantum effects also penetrate into technology and they are expected to gain more ground in the technological developments in the very near future. Some well-known examples from this field include quantum computing and molecular quantum switches. The fast development of quantum theory and its applications always required extensive experimental contributions, mostly in the field of spectroscopy. By this project, we will contribute to understanding the details of some quantum effects. The experiments will be done on a unique setup at ELTE – Eötvös University. The experiments, performed below 4 K in a special solid quantum host, para-hydrogen, will allow distinguishing between classical and quantum effects. The experimental results can help to further understand and develop quantum theory and develop molecular switches applicable in modern technology.