Robert J. Donovan

Cellular telephone transmission of 12-lead electrocardiograms from ambulance to hospital

Currently, only single-lead, serial telemetry rhythm strips can be transmitted from ambulances. Triage of patients with chest pain and administration of thrombolytic therapy in ambulances is limited by the lack of specific electrocardiographic (ECG) diagnosis. A new technique is described using cellular telephone transmission of simultaneous 12-lead ECGs from ambulance to hospital to overcome this limitation. A portable 12-lead ECG installed in an ambulance was connected via modern link to a cellular telephone and digitized ECG information was transmitted to an ECG device in the hospital emergency room. Paramedics in the field placed adhesive patch electrodes and attached ECG wires. Field ECGs from 23 patients were compared with corresponding transmitted ECGs. There were no differences in heart rate, PR interval, QRS duration, QT interval or R- and T-wave axes. Baseline and transmitted ECGs had identical morphologic characteristics. Differences in R-wave amplitude in 5 transmitted tracings compared with hospital-recorded ECGs resulted in computer diagnosis of left ventricular hypertrophy by voltage, possibly due to differences in patient position. Twelve-lead ECGs can be easily transmitted from a moving ambulance using cellular telephones. This allows diagnosis before hospital arrival, improves prehospital triage of patients and may facilitate prehospital therapy with lidocaine or streptokinase. In addition, the cellular telephone link can convey both verbal and digitized information and thus improve on current telemetry systems.

EINSTEIN A-COEFFICIENTS AND TRANSITION DIPOLE-MOMENTS FOR SOME ION-PAIR TO VALENCE TRANSITIONS IN I2

The relative fluorescence intensities of all the strong electronic transitions from five of the first cluster of ion-pair (IP) states of I2 and from three states in the second cluster have been measured. The fluorescence, in most cases from ν′ = 0, was dispersed and comprised both discrete and continuous (bound → free) spectra. These were fitted and each simulated electronic spectrum integrated separately to give relative values of the Einstein A-coefficients (summed over final vibrational states) for each transition. Using previously reported lifetimes, transition dipoles for each of the parallel transitions from nine IP states are deduced, together with some of the stronger perpendicular transition dipole moments. At R e of the ion-pair states, μ‖ (five transitions observed) is almost constant at 0·2–0·3 D, but μ‖ ranges between 0·7 and 3·7 D. There is a marked difference in the parallel transition moments associated with some g/u pairs in the same cluster of IP states which can be accounted for by the ...

Spectroscopy and electronic structure of ion-pair states

Ion-pair states are a distinctive sub-set of the valence states of molecules. In a few cases they constitute the ground electronic state, but more usually their term values lie close to the lowest Rydberg states. Their unusual spectroscopic properties and the techniques used to access them are discussed with particular reference to the diatomic halogens. Their electronic structure is best approached from two complementary points of view, as a single molecular orbital configuration or the product of separated ion configurations, according to the ionic separation. The consequences of this dual character for absorption and fluorescence spectroscopy are outlined. Finally, the state-specific coupling of Rydberg and ion-pair states is surveyed.

Re-analysis of the ultraviolet absorption spectrum of ozone

A re-analysis of the Huggins and Hartley bands in the ultraviolet absorption spectrum of O3 is presented in which the structure in both bands is assigned to vibrational progressions in the symmetric stretching mode ν1 and the bending mode ν2 but not the asymmetric stretching mode ν3. The present improved fit of a larger range of bands results in relatively large anharmonicity terms, whereas previous assignments have relied on the motion being largely harmonic in the upper state. From a consideration of the shape of single surface required to support both sets of vibrational data, it is concluded that the Huggins bands almost certainly terminate on the 2u20091A1 state rather than the 1u20091B2 state.

Ultraviolet laser multiphoton excitation of CH2I2

Laser multiphoton excitation of CH2I2 has been studied at 248 nm (KrF laser) and 193 nm (ArF laser). Intense photofragment fluorescence is observed from CH(A2Δ), with weaker fluorescence from CH(B2Σ–) and CH(C2Σ+), following excitation at both wavelengths. The rotational structure in the CH(A2Δ→X2Π) system has been partially resolved and it is shown that this radical is formed with a high rotational temperature (ca. 3000 K) when CH2I2 is excited at 248 nm. Fluorescence from I(5p46s2P3/2) and the F1Σ+u, D1Σ+u and D′3Π2g states of I2 is also observed and carbon atoms in the 21D2 and 21S0 states are detected by laser-induced fluorescence. Mechanisms which account for the formation of these photofragments involving both multiphoton and multiple-photon excitation are discussed and the results are compared with those for single-photon excitation of CH2I2 in the near and vacuum ultraviolet.

Evidence for Rydberg Doorway States in Photoion Pair Formation in Bromomethane

The vacuum ultraviolet laser-excited photoion-pair formation spectrum of CH 3Br has been measured under high resolution in the threshold region. The (2 + 1) and (3 + 1) resonance-enhanced multiphoton ionization spectra in the same energy region are also reported. By comparison of the spectra in this and a more extended region, resonances in the photoion-pair formation spectrum are assigned to p and f Rydberg states. It is concluded that all the structure in the photoion-pair formation spectrum near threshold can be accounted for by members of the Omega = 0 subset of Rydberg states that act as doorway states to the ion channel.

Kinetic energy analysis of O(3P0) and O2(b 1Σg+) fragments produced by photolysis of ozone in the Huggins bands

The velocity profile of O2(bu200a1Σg+,v=0) produced by photolysis of O3 in the Huggins band region at 351.4 nm has been measured using a delayed pulsed field extraction time-of-flight technique confirming that this fragment is formed by single-photon absorption. The velocity profile of O(3P0) produced by photolysis at 322.64 nm has also been obtained. O(3P0) fragments are shown to be produced in coincidence with O2(Xu200a3Σg−), O2(au200a1Δg), and O2(bu200a1Σg+). The relative contribution of each of these channels to the total O(3P0) signal is reported and it is shown that spin-forbidden channels dominate the dissociation process at this wavelength. Two quite different primary crossings of the initially excited state are suggested to account for the change in the relative contribution of these three channels when photolysis is changed from resonance with a vibronic band of ozone to an off-resonance wavelength. The determination of the anisotropy parameter, β(v), for these dissociation processes suggests that the transitio...

Mass‐resolved multiphoton ionization spectroscopy of jet‐cooled Cl2. I. Bound‐free‐bound spectroscopy

Spectroscopic constants, obtained using two‐color optical double resonance via repulsive intermediate states, are presented for four ion‐pair states of Cl2; i.e., the E(0+g), β(1g), f(0+g), and G(1g) states. One‐color excitation, also via a repulsive intermediate state, has been used to further extend the vibrational data for the β(1g) state. The same pumping scheme has been used to extend a vibrational progression in the [2Π1/2]c4s; 1g Rydberg state. The absence of perturbations when the [2Π1/2]c4s; 1g Rydberg and the β(1g) ion‐pair states cross, together with the key role played by the intermediate C(1u) state in accessing both singlet and triplet final states, are discussed in terms of the changes in spin–orbital coupling schemes that are required on bond stretching.

Amplified spontaneous emission and collisional transfer from the f0g+(P30) ion-pair state of I2

The work presented here extends previous studies of amplified spontaneous emission (ASE) between ion-pair (charge-transfer) states of I(2) and shows that ASE can occur between states correlating with different states of the cation, namely, f0(g)(+)((3)P(0)) and D0(u)(+)((3)P(2)), despite the smaller transition dipole moment between them. A value of 0.34 e A is obtained for the transition dipole under experimental conditions where the f0(g)(+)((3)P(0))-->D0(u)(+)((3)P(2)) ASE is eliminated. No F0(u)(+)((3)P(0))<--f0(g)(+)((3)P(0)) ASE transfer is observed despite the combination of favorable Franck-Condon factors and transition dipoles. The F0(u)(+)((3)P(0))<--f0(g)(+)((3)P(0)) transfer is shown to be purely collisional and a propensity for transfers involving the smallest energy mismatch is observed.

Ionic and Rydberg states of CF3I studied by high resolution photoelectron (ZEKE-PFI) and resonance-enhanced multiphoton ionisation spectroscopy

Ionic and Rydberg states of CF3I have been studied using both zero kinetic energy pulsed-field ionisation (ZEKE-PFI) photoelectron and resonance-enhanced multiphoton ionisation (REMPI) spectroscopy. The ground state of the ion (2E3/2) was characterised using coherent two-photon (one-colour) ZEKE-PFI spectroscopy and extended progressions in the symmetric vibrational modes, similar to those observed in the conventional He(I) photoelectron spectrum, were observed at high resolution. The [2E3/2]6p Rydberg states were studied using two- and three-photon REMPI spectroscopy with linearly and circularly polarised light. This resulted in the assignment of at least three states with distinct Ω values (2, 1 and 0) with the Ω=2 components being the most intense. The strongest members of the [2E3/2]6p;2 system were used as resonant intermediates in two-colour (2+1′) ZEKE-PFI experiments which allowed the unambiguous assignment of the majority of the vibrational structure of the intermediate states. The adiabatic ionisation energy of CF3I was determined as 83652±2 cm-1. The vibrational structure observed for one of the Ω=2 components of the [2E3/2]6p cluster in CF3I differs considerably from that observed for the lower lying 6s states and the analogous 6p states of CH3I. In particular, ν3 (the carbon–iodine stretch) shows a vibrational frequency substantially reduced from that of the neutral and ionic ground states. It is concluded that at least one of the [2E3/2]6p states of CF3I is distorted, possibly through an interaction with an ion-pair state.