Gaussians for Electronic and Rovibrational Quantum Dynamics.

The assumptions underpinning the adiabatic Born-Oppenheimer (BO) approximation are broken for molecules interacting with attosecond laser pulses, which generate complicated coupled electronic-nuclear wave packets that generally will have components of electronic and dissociation continua as well as bound-state contributions. The conceptually most straightforward way to overcome this challenge is to treat the electronic and nuclear degrees of freedom on equal quantum-mechanical footing by not invoking the BO approximation at all. Explicitly correlated Gaussian (ECG) basis functions have proved successful for non-BO calculations of stationary molecular states and energies, reproducing rovibrational absorption spectra with very high accuracy. In this Article, we present a proof-of-principle study of the ability of fully flexible ECGs (FFECGs) to capture the intricate electronic and rovibrational dynamics generated by short, high-intensity laser pulses. By fitting linear combinations of FFECGs to accurate wave function histories obtained on a large real-space grid for a regularized 2D model of the hydrogen atom and for the 2D Morse potential, we demonstrate that FFECGs provide a very compact description of laser-driven electronic and rovibrational dynamics.

Modeling of High-Harmonic Generation in the C60 Fullerene Using Ab Initio, DFT-Based, and Semiempirical Methods.

We report calculations of the high-harmonic generation spectra of the C60 fullerene molecule carried out by employing a diverse set of real-time time-dependent quantum chemical methods. All methodologies involve expanding the propagated electronic wave function in bases consisting of the ground and singly excited time-independent eigenstates obtained through the solution of the corresponding linear-response equations. We identify the correlation and exchange effect in the spectra by comparing the results from methods relying on the Hartree-Fock reference determinant with those obtained using approaches based on the density functional theory with different exchange-correlation functionals. The effect of the full random-phase approximation treatment of the excited electronic states is also analyzed and compared with the configuration interaction singles and the Tamm-Dancoff approximation. We also showcase the fact that the real-time extension of the semiempirical method INDO/S can be effectively applied for an approximate description of laser-driven dynamics in large systems.

Efficacy of Fractional CO2 Laser Treatment for Genitourinary Syndrome of Menopause in Short-Term Evaluation-Preliminary Study.

The postmenopausal state covers 40% of modern women's lives and 50-70% of postmenopausal women report GSM symptoms such as vaginal dryness, itching, frequent inflammations, lack of elasticity, or dyspareunia. Consequently, a safe and effective method of treatment is crucial. In a group of 125 patients, a prospective observational study was performed. The aim was to evaluate the clinical effectiveness of fractional CO2 laser in the treatment of GSM symptoms using a protocol of three procedures in 6-week intervals. The vaginal pH, VHIS, VMI, FSFI, and treatment satisfaction questionnaire were used. The fractional CO2 laser treatment was effective in improving all the objective forms of evaluation: vaginal pH (from 5.61 ± 0.50 at the baseline up to 4.69 ± 0.21 in the 6-week follow-up after the third procedure); VHIS (12.02 ± 1.89 at the baseline vs. 21.50 ± 1.76); VMI (21.5 ± 5.66 vs. 48.4 ± 4.46). Similar results were obtained for FSFI: 12.79 ± 5.351 vs. 24.39 ± 2.733, where 79.77% of patients were highly satisfied. Fractional CO2 laser therapy increases the quality of life by having a beneficial effect on the sexual function of women with GSM symptoms. This effect is obtained by restoring the correct structure and proportions of the cellular composition of the vaginal epithelium. This positive effect was confirmed by both objective and subjective forms of evaluating GSM symptom severity.

Effects of electronic correlation on the high harmonic generation in helium: A time-dependent configuration interaction singles vs time-dependent full configuration interaction study.

In this paper, we investigate the effects of full electronic correlation on high harmonic generation in the helium atom subjected to laser pulses of extremely high intensity. To do this, we perform real-time propagations of helium atom wavefunction using quantum chemistry methods coupled to Gaussian basis sets. Calculations are performed within the real-time time-dependent configuration interaction framework at two levels of theory: time-dependent configuration interaction with single excitations (uncorrelated method) and time-dependent full configuration interaction (fully correlated method). The electronic wavefunction is expanded in Dunning basis sets supplemented with functions adapted to describing highly excited and continuum states. We also compare the time-dependent configuration interaction results with grid-based propagations of the helium atom within the single-active-electron approximation. Our results show that when including the dynamical electron correlation, a noticeable improvement to the description of high harmonic generation (HHG) can be achieved in terms of, e.g., a more constant intensity in the lower energy part of the harmonic plateau. However, such effects can be captured only if the basis set used suffices to reproduce the most basic features, such as the HHG cutoff position, at the uncorrelated level of theory.

Ultrasonographic signs of acute ovarian torsion.

Ovarian torsion is defined as partial or complete rotation of the ovarian vascular pedicle and causes obstruction to venous outflow and arterial inflow. Teenage patient was referred to the gynecology ward with pain located in the lower, right abdomen, after an initial misdiagnosis of a dermoid cyst. The patient was diagnosed with a torsion of the right ovarian peduncle. The patient was given diastolic drugs and was discharged in good general condition two days later after the symptoms had resolved. Final USG showed normally vasculated corpus luteum. Among the various treatment options, the wait-and-watch attitude turned out to be the best solution. It is particularly important in the case of young patients, who are planning pregnancy in the future.

A systematic construction of Gaussian basis sets for the description of laser field ionization and high-harmonic generation.

A precise understanding of mechanisms governing the dynamics of electrons in atoms and molecules subjected to intense laser fields has a key importance for the description of attosecond processes such as the high-harmonic generation and ionization. From the theoretical point of view, this is still a challenging task, as new approaches to solve the time-dependent Schrödinger equation with both good accuracy and efficiency are still emerging. Until recently, the purely numerical methods of real-time propagation of the wavefunction using finite grids have been frequently and successfully used to capture the electron dynamics in small one- or two-electron systems. However, as the main focus of attoscience shifts toward many-electron systems, such techniques are no longer effective and need to be replaced by more approximate but computationally efficient ones. In this paper, we explore the increasingly popular method of expanding the wavefunction of the examined system into a linear combination of atomic orbitals and present a novel systematic scheme for constructing an optimal Gaussian basis set suitable for the description of excited and continuum atomic or molecular states. We analyze the performance of the proposed basis sets by carrying out a series of time-dependent configuration interaction calculations for the hydrogen atom in fields of intensity varying from 5 × 1013 W/cm2 to 5 × 1014 W/cm2. We also compare the results with the data obtained using Gaussian basis sets proposed previously by other authors.

Theoretical modeling of DNA electron hole transport through polypyrimidine sequences: a QM/MM study.

The phenomenon of DNA hole transport (HT) has attracted of scientists for several decades, mainly due to its potential application in molecular electronics. As electron holes mostly localize on purine bases in DNA, the majority of scientific effort has been invested into chemically modifying the structures of adenine and guanine in order to increase their HT-mediating properties. In this work we examine an alternative, never yet explored, way of affecting the HT efficiency by forcing electron holes to localize on pyrimidine bases and move between them. Using an enhanced and revised version of our previously developed QM/MM model, we perform simulations of HT through polyadenine, polycytosine, polyguanine, and polythymine stacks according to a multistep hopping mechanism. From these simulations, kinetic parameters for HT are obtained. The results indicate a particularly high efficiency of cytosine→cytosine hopping, which is about ten times higher than the G → G hopping. We also discuss possible improvement of cytosine HT by modifying the oxidoreductive properties of complementary guanine residues.