Silver Salt Enabled H/D Exchange at β Position of Thiophene Rings: Synthesis of Fully Deuterated Thiophene derivatives

We disclose a silver catalyzed H/D exchange reaction, which can introduce deuterium atom at β position of thiophene rings without the assisstance of any coordinating groups. The advantages of this...

Magic Wavelengths for 1S–nS and 2S–nS Transitions in Hydrogenlike Systems

We study the magic wavelength for two-photon 1S–nS transitions in a hydrogen and deuterium atom, as well as 2S–nS transitions, where the lower level is the metastable 2S state. At the magic wavelength, the dynamic Stark shifts of the ground and the excited state of the transition coincide, so that the transition frequency is independent of the intensity of the trapping laser field. Experimentally feasible magic wavelengths of transitions with small slopes in the atomic polarizabilities are determined; these are the most stable magic wavelengths against variations of the laser frequency. We provide data for the magic wavelengths for the 1S–nS and 2S–nS transitions in hydrogen and deuterium, with n=2,⋯,8. We also analyze the stability of the elimination of the ac Stark shift at the magic wavelength against tiny variations of the trapping laser frequency from the magic value.

Classical Analytical Description of Negative Hydrogen Ions

Studies of negative hydrogen ions (hereafter, NHI), such as, H– and D–, are important from both practical and fundamental points of view. One of the reasons for practical importance has to do with heating tokamak plasmas by external beams of NHI. Another practical use is the injection of NHI in high power proton accelerator facilities – for enhancing their performance. In addition, NHI are also important for studies of opacities of the atmospheres of the Sun and of the A-type stars. We present a classical analytical description of NHI in the situation where the underlying hydrogen (or deuterium) atom constitutes a rapid subsystem while the outer electron represents a slow subsystem. We focus at the case where the inner electron is in a circular state, so that the subsystem “nucleus plus inner electron” does not have the average electric dipole moment – in distinction to previous studies where the presence of the average dipole moment was the crucial requirement. By using the separation of rapid and slow subsystems, we show analytically that there is a classical bound state in such system and studied its parameters. In particular, we calculate analytically the primary frequency of the radiation of such system. This could be used for its experimental detection. The states that we found for the above systems could be considered as classical counterparts of the double-excited states of NHI previously studied in the literature in frames of quantum mechanics. The existence of classical counterparts of the double-excited states of NHI is a counterintuitive result.

Inequality in the Frequency of the Open States Occurrence Depends on Single 2H/1H Replacement in DNA

In the present study, the effect of 2H/1H isotopic exchange in hydrogen bonds between nitrogenous base pairs on occurrence and open states zones dynamics is investigated. These processes are studied using mathematical modeling, taking into account the number of open states between base pairs. The calculations of the probability of occurrence of open states in different parts of the gene were done depending on the localization of the deuterium atom. The mathematical modeling study demonstrated significant inequality (dependent on single 2H/1H replacement in DNA) among three parts of the gene similar in length of the frequency of occurrence of the open states. In this paper, the new convenient approach of the analysis of the abnormal frequency of open states in different parts of the gene encoding interferon alpha 17 was presented, which took into account both rising and decreasing of them that allowed to make a prediction of the functional instability of the specific DNA regions. One advantage of the new algorithm is diminishing the number of both false positive and false negative results in data filtered by this approach compared to the pure fractile methods, such as deciles or quartiles.

Mathematical Modeling of Open States in Double Stranded DNA Molecule Depending on 2H/1H Ratio

The evaluation results of the possible deuterium atoms effect on the DNA base pair opening are presented in the article. The cause of these processes is the replacement of protium with deuterium atom due to the increase of energy required to break the hydrogen bond. These processes can be studied by method of mathematical modeling, with account of open states between base pairs being the key condition of the adequacy of the mathematical model of the DNA. The experiment data show that the presence of deuterium in a chain of nucleotides can cause - depending on the value of hydrogen bond disruption energy - both increase and decrease in probability of open states occurrence. For example: hydrogen bond disruption energy of 0.358·10-22 n·m, non-zero probability of open states occurrence is observed in case of the absence of deuterium in the molecule, and with hydrogen bond disruption energy of 0.359·10-22 n·m or more such probability equals zero. Also, when one deuterium atom is present in a molecule, non-zero probability is observed even with hydrogen bond disruption energy equal to 0.368·10-22 n·m (i.e. more than 0.358·10-22 n·m). Thus participation of deuterium atoms in the formation of hydrogen bonds of double helixes of a DNA molecule can cause the changes in the time required for transfer of genetic information, which can explain the effect of even minor deviations in deuterium concentration in a medium on metabolic processes in a living system.