Using a time-dependent multilevel approach,we demonstrate that lithium atoms can be transferred to states of lower principle quantum number by exposing them to a frequency chirped microwave pulse.The population transfer from n=79 to n=70 states of lithium atoms with more than 80% efficiency is achieved by means of the sequential two-photon n= 1 transitions.It is shown that the coherent control of the population transfer can be accomplished by the optimization of the chirping parameters and microwave field strength.The calculation results agree well with the experimental ones and novel explanations have been given to understand the experimental results.
Optimized geometry and harmonic vibrational frequency of 2-dicyanovinyl-5-(4- ethoxyphenyl)thiophene (C16H12N2OS) are calculated at the HF/6-31++G(d,p) and B3LYP/6- 311++G(d,p) levels. Mulliken charges in the ground state are also calculated. The research shows the presence of intermolecular interaction in the title compound. The scaled harmonic vibrational frequencies have been compared with experimental FT-IR spectra. A detailed interpretation of the infrared spectra of the title compound is reported. The theoretical spectrograms for IR spectra of the title compound have been constructed. The isotropic chemical shift computed by 13C and 1H NMR analyses also shows good agreement with the experimental observations.
Secure key distribution among classical parties is impossible both between two parties and in a network. In this paper, we present a quantum key distribution (QKD) protocol to distribute secure key bits among one quantum party and numerous classical parties who have no quantum capacity. We prove that our protocol is completely robust, i.e., any eavesdropping attack should be detected with nonzero probability. Our calculations show that our protocol may be secure against Eve’s symmetrically individual attack.
