No abstract

We re-examine the ionization-detected ultraviolet absorption spectrum of the 3pπ 2Π←X 2A′ transition in HCO and DCO using a high-power visible laser to enhance the observation of first-photon resonant features. This technique, which we term here, assisted REMPI, significantly improves the signal-to-noise ratio of the spectrum, making many weak vibronic sub-bands visible for the first time. A comprehensive fit to the structure evident in a progression of bending levels from (000) to (040) refines the assignment of Song and Cool [X. M. Song and T. A. Cool, J. Chem. Phys. 96, 8664 (1992)] to yield a set of rotational constants that vary with K in relation to v2, together with a higher-order contribution to the Renner–Teller splitting in HCO, which is mirrored in DCO for all levels but (040). The (040) band falls at a frequency that is commensurate with that of CD stretch, and Fermi resonance between 3pπ 2Π(1000)Π and the higher-energy (040) K=1(Π) component gives rise to an added splitting that increases the energy of this (040) component and causes an apparent increase in the Renner parameter.

This study explored some quandaries concerning craving and mood as motivators to smoke. Craving and negative mood have long been associated with day-today smoking as two of the primary motivational forces behind the maintenance of the behavior, as well as significant barriers in smokers' attempts to quit. Craving remains a clinically relevant phenomenon, with most smokers describing craving as a troublesome problem when quitting. Smokers' self-reports of negative mood, as an antecedent for smoking, are so robustly reported that many models of nicotine dependence have incorporated a critical role for negative mood in maintaining smoking behavior. However, several naturalistic studies that collected mood ratings with hand held computers from smokers in real time, just before smoking a cigarette, have provided scant evidence that negative mood plays a major role in motivation to smoke. No study to date has examined craving and mood data as a consequence of smoking, that is, collecting the same data immediately after smoking. This study used personal digital assistants (PDAs) to collect craving and mood data immediately before smoking, immediately after smoking, and at random times of day. Nontreatment seeking smokers (N=72) carried a PDA for an average of 10 days while they recorded their smoking behavior. Results showed that craving and negative mood ratings were lowest immediately after smoking compared with immediately before smoking and at random times of day. These findings suggest that smokers may be at least partially motivated to smoke to lower their craving and improve their mood states.

No abstract

We report the ionization-detected absorption spectra of autoionizing Rydberg states converging to the (010) vibrational level of HCO+. Sharp second-photon resonances appear in transitions from first-photon-prepared originating states that have total angular momentum (less-spin) from N′=0 to 5, selected from the Σ+ and Σ− components of the (010) band of the 3pπ2Π Rydberg state. We systematically compare spectra in order to characterize observed resonances in terms of the good total angular momentum quantum number, N. Rydberg analysis establishes the convergence of series to detailed cation-core rotational quantum numbers, N+. Observed series are found to fit well with simulations employing a limited set of constant quantum defects (δ=1.062, 0.794, 0.606, 0.253, 0.015, 0.002, −0.027 and −0.076). The strengths of observed transitions as a function of initial and final total angular momentum provide a purely experimental indication of the appropriate assignment of the approximately good orbital angular momentum quantum number, l, for each series. Interactions between Rydberg orbital and core rotational angular momentum are found to conform with a coupling case intermediate between Hund’s cases (b) and (d). Splitting patterns further assign certain features according to predominant case (b) composition.