Rotational analysis of the 6480 Å absorption of NO2

1979 ◽  
Vol 57 (3) ◽  
pp. 428-441 ◽  
Author(s):  
J. C. D. Brand ◽  
K. J. Cross ◽  
A. R. Hoy
Keyword(s):  
Vibrational Level ◽  
Vibronic Coupling ◽  
Spin Splitting ◽  
Order Effects ◽  
Centrifugal Distortion ◽  
Vibronic Band ◽  
Visible Absorption ◽  
Centrifugal Distortion Constants ◽  
Franck Condon ◽  
Higher Order Effects

About 300 rotational transitions in the 6480 Å region in the visible absorption of NO2 gas have been assigned by laser-excited fluorescence. A majority of the stronger transitions belong to the K = 0 and K = 1 subbands of a vibronic band, T0 = 15 434.9 cm−1, whose upper state is predominantly an a1, vibrational level of the electronic 2B2 basis state. Other groups of relatively weaker lines form (i) a severely-perturbed K = 2 subband attributed to the same series as the K = 0 and 1 subbands; (ii) a well-developed though relatively weak K = 3 subband assigned to a hybrid level of mainly 2A1, character, the transition to this level being induced by vibronic coupling; and (iii) a K = 6 subband assigned to a parent (i.e., 2B2 basis) vibrational level different from that identified at 15 435 cm−1. The spectrum in this region abundantly illustrates the irregularities, 'extra' lines, resonance crossings, and erratic spin splitting now recognized as widespread in the NO2 visible absorption. Rotational constants are not well defined and vary considerably from one subband to another: large pseudo-centrifugal distortion constants are attributed to higher-order effects of the vibronic coupling. Franck–Condon analysis of the intensity distribution in fluorescence leads to a tentative vibrational assignment of 1 60 for the stale at 15 435 cm−1.

The 2491 Å band system of NO2. Rotational structure and evidence for predissociation in the zero-point level

1976 ◽  
Vol 54 (11) ◽  
pp. 1157-1171 ◽  
Author(s):  
K. -E. J. Hallin ◽  
A. J. Merer
Keyword(s):  
Vibrational Level ◽  
Band System ◽  
Zero Point ◽  
Spin Rotation ◽  
Rotational Analysis ◽  
Coupling Constant ◽  
Centrifugal Distortion ◽  
Minimum Potential ◽  
Centrifugal Distortion Constants ◽  
Point Level

A detailed rotational analysis of the (0, 0) band of the [Formula: see text] electronic transition of NO2, at 2491 Å, has been carried out. Although the lines are slightly broadened as a result of predissociation, it has been possible to determine the five quartic centrifugal distortion constants and the spin–rotation coupling constant εaa for the upper state. The centrifugal distortion constants allow the position of the unseen vibrational level ν3′ to be estimated: the results offer no support to the suggestion of Coon, Cesani, and Huberman that there is a double minimum potential function in the antisymmetric stretching coordinate of the 2B2 state. The geometric structure of the zero-point level of the 2B2 state is r(N—O) = 1.3142 Å, [Formula: see text], and its lifetime (as calculated from the linewidths) is 42 ± 5 ps.

Time after time: support for memory accounts of temporal preparation.

2019 ◽  
Author(s):  
Joe Butler ◽  
Samuel Ngabo ◽  
Marcus Missal
Keyword(s):  
Response Times ◽  
Reaction Times ◽  
Evidence Base ◽  
Higher Order ◽  
Order Effects ◽  
Previous Trial ◽  
Adaptive Responses ◽  
Temporal Preparation ◽  
Subsequent Trial ◽  
Higher Order Effects

Complex biological systems build up temporal expectations to facilitate adaptive responses to environmental events, in order to minimise costs associated with incorrect responses, and maximise the benefits of correct responses. In the lab, this is clearly demonstrated in tasks which show faster response times when the period between warning (S1) and target stimulus (S2) on the previous trial was short and slower when the previous trial foreperiod was long. The mechanisms driving such higher order effects in temporal preparation paradigms are still under debate, with key theories proposing that either i) the foreperiod leads to automatic modulation of the arousal system which influences responses on the subsequent trial, or ii) that exposure to a foreperiod results in the creation of a memory trace which is used to guide responses on the subsequent trial. Here we provide data which extends the evidence base for the memory accounts, by showing that previous foreperiod exposures are cumulative with reaction times shortening after repeated exposures; whilst also demonstrate that the higher order effects associated with a foreperiod remain active for several trials.

scholarly journals Responsible innovation, anticipation and responsiveness: case studies of algorithms in decision support in justice and security, and an exploration of potential, unintended, undesirable, higher-order effects

AI and Ethics ◽  
2021 ◽  
Author(s):  
Marc Steen ◽  
Tjerk Timan ◽  
Ibo van de Poel
Keyword(s):  
Decision Support ◽  
Case Studies ◽  
Personal Data ◽  
Higher Order ◽  
Popular Media ◽  
Responsible Innovation ◽  
Order Effects ◽  
Key Dimensions ◽  
Higher Order Effects

AbstractThe collection and use of personal data on citizens in the design and deployment of algorithms in the domain of justice and security is a sensitive topic. Values like fairness, autonomy, privacy, accuracy, transparency and property are at stake. Negative examples of algorithms that propagate or exacerbate biases, inequalities or injustices have received ample attention, both in academia and in popular media. To supplement this view, we will discuss two positive examples of Responsible Innovation (RI): the design and deployment of algorithms in decision support, with good intentions and careful approaches. We then explore potential, unintended, undesirable, higher-order effects of algorithms—effects that may occur despite good intentions and careful approaches. We do that by engaging with anticipation and responsiveness, two key dimensions of Responsible Innovation. We close the paper with proposing a framework and a series of tentative recommendations to promote anticipation and responsiveness in the design and deployment of algorithms in decision support in the domain of justice and security.

scholarly journals Probing intramolecular vibronic coupling through vibronic-state imaging

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Fan-Fang Kong ◽  
Xiao-Jun Tian ◽  
Yang Zhang ◽  
Yun-Jie Yu ◽  
Shi-Hao Jing ◽  
...  
Keyword(s):  
Single Molecule ◽  
Molecular Spectroscopy ◽  
Transition Density ◽  
Real Space ◽  
Vibronic Coupling ◽  
Vibronic State ◽  
Dipole Orientation ◽  
Transition Dipole ◽  
Franck Condon ◽  
Strong Dynamic

AbstractVibronic coupling is a central issue in molecular spectroscopy. Here we investigate vibronic coupling within a single pentacene molecule in real space by imaging the spatial distribution of single-molecule electroluminescence via highly localized excitation of tunneling electrons in a controlled plasmonic junction. The observed two-spot orientation for certain vibronic-state imaging is found to be evidently different from the purely electronic 0–0 transition, rotated by 90°, which reflects the change in the transition dipole orientation from along the molecular short axis to the long axis. Such a change reveals the occurrence of strong vibronic coupling associated with a large Herzberg–Teller contribution, going beyond the conventional Franck–Condon picture. The emergence of large vibration-induced transition charges oscillating along the long axis is found to originate from the strong dynamic perturbation of the anti-symmetric vibration on those carbon atoms with large transition density populations during electronic transitions.

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