ABSTRACT
The cross sections for the formation of the H(2p) and H(2s) atoms, σ 2p and σ 2s , respectively, in photoexcitation of C2H2 were obtained in an absolute scale for studying formation and decay of superexcited states in the extreme ultraviolet range. Several superexcited states of C2H2 including multiply excited states were found in the curve of the σ 2p cross sections as a function of the incident photon energy. The same states seem to contribute to the variation in the σ 2s cross sections as well, which can be ascribed to the non-adiabatic transitions between the 2p and 2s channels. The Σ/Π symmetry-resolved cross sections for the H(2s) atom formation, σ 2 s Σ and σ 2 s Π , were also obtained on an absolute scale. The coupling between the Σ u + 1 and 1Π u states was found to be small.
ABSTRACT
The absolute cross sections for the formation of the H(2s) and H(2p) atoms, σ2s and σ2p, respectively, in photoexcitation of CH4 and NH3 were measured in the range of the incident photon energy 15-48 eV for studying superexcited states of the molecules. The same superexcited states were found to contribute to the σ2s and σ2p cross sections. It was concluded that the non-adiabatic transitions play a significant role during the dissociation of the superexcited states and ionic states.
ABSTRACT
The two dissociative ionization channels of ethanol (C2H5OH) induced by an intense near-infrared laser pulse (λ ~ 783 nm), C2H5OH â CH2OH(+) + CH3 + e(-) and C2H5OH â C2H5(+) + OH + e(-), are investigated using photoelectron-photoion coincidence method. It is shown that both the electronic ground state and the first electronically excited state of C2H5OH(+) are produced at the moment of photoelectron emission. From the observed correlation between the electronic states of C2H5OH(+) prepared at the moment of photoelectron emission and the kinetic energy release of the fragment ions, it is revealed that C2H5OH(+) prepared in the electronic ground state at the photoelectron emission gains larger internal energy in the end than that prepared in the electronically excited state. The averaged internal energy of C2H5OH(+) just before the dissociation is found to increase when the laser field intensity increases from 9 to 23 TW∕cm(2) and when the laser pulse duration increases from 35 to 800 fs.
Subject(s)
Ethanol/chemistry , Lasers , Electrons , Photochemical ProcessesABSTRACT
Wave functions of electrically neutral systems can be used as information carriers to replace real charges in the present Si-based circuit, whose further integration will result in a possible disaster where current leakage is unavoidable with insulators thinned to atomic levels. We have experimentally demonstrated a new logic gate based on the temporal evolution of a wave function. An optically tailored vibrational wave packet in the iodine molecule implements four- and eight-element discrete Fourier transform with arbitrary real and imaginary inputs. The evolution time is 145 fs, which is shorter than the typical clock period of the current fastest Si-based computers by 3 orders of magnitudes.
ABSTRACT
We numerically propose a way to perform quantum computations by combining an ensemble of molecular states and weak laser pulses. A logical input state is expressed as a superposition state (a wave packet) of molecular states, which is initially prepared by a designed femtosecond laser pulse. The free propagation of the wave packet for a specified time interval leads to the specified change in the relative phases among the molecular basis states, which corresponds to a computational result. The computational results are retrieved by means of quantum interferometry. Numerical tests are implemented in the vibrational states of the B state of I2 employing controlled-NOT gate, and 2 and 3 qubits Fourier transforms. All the steps involved in the computational scheme, i.e., the initial preparation, gate operation, and detection steps, are achieved with extremely high precision.
