The Impact of Pulse Shaping on Coherent Dynamics near a Conical Intersection
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsPlease see the report as attached.
Comments for author File: 
Comments.pdf
A major revision including English edition is required.
Author Response
Thank you very much for your acknowledgment of our work and for your valuable suggestions, which have greatly enhanced the professionalism of our paper. The specific details of the revisions are outlined in the documents we have submitted.
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsReferee report for the manuscript "The Impact of Pulse Shape on Coherent Dynamics near Conical Intersection" by Qici Deng, Junjie Yu, Hongguang Duan and Hongxing He, submitted to Photonics.
The manuscript by Deng et al. explores ultrashort pulse manipulation for investigating reaction dynamics involving conical intersections (CIs). The main idea of the work is to use a three-state model to investigate the vibrationally coherent dynamics of an electronic wave packet near a CI. The authors utilize the time non-local quantum master equation to calculate the time-evolution dynamics of the system on excited-state potential energy surfaces and then evaluate the wave-packet projections onto effective reaction coordinates. By manipulating the excitation pulse beam temporal profile, the authors have revealed a dependence of the excited state relaxation, originated by different preparations of the coherent wave packet, implying also different quantum yields.
In my opinion, the results presented in the manuscript are overall scientifically sound and worthy of publication. However, some crucial points remain obscure or unclear. The manuscript contains several typos that impair readability, making the overall draft extremely difficult to read. In addition, several references, relevant for the subject of research focus of this paper, should be cited for stressing the novelty and the impact of the presented approach.
For these reasons, I cannot recommend publication in the present form, and I suggest a major revision. Below a detailed list of points to be addressed.
Major points:
1) The citation to recent literature is definitively inaccurate and incomplete. An outlook on theoretical and experimental works exploiting coherent control to manipulate the reaction pathways of photoexcited molecules would be in order. Some relevant examples include: 10.1126/science.1130747, 10.1103/PhysRevLett.109.243001, 10.1103/PhysRevLett.114.233003.
2) Lines 43-45: the sentence “With the better time resolution, the recently developed FSRS reexamined the isomerization process and its timescale has been measured to be shorter than 50 fs” should not mention a “better time resolutions”. In fact, the experiment discussed here does not have an improved temporal resolution with respect to the previously mentioned one. In this respect, the authors should have a look to the seminal works by Mukamel on the resolution limits of FSRS.
3) Lines 47-49: “Moreover, the two-dimensional FSRS has been recently constructed and applied to study the anharmonicity of the vibrational coherence of charge-transfer modes of an artificial dimer system [15–17].” The mentioned references are not appropriately cited nor "recent". Ref. 15 contradicts the authors' assertion ("the observed signal cannot be probing molecular anharmonicity"). Ref. 17 is an aged review on FSRS where the technique is erroneously presented as the way to circumvent the Heisenberg principle. More appropriate works are: 10.1002/lpor.200900048, 10.1021/acs.jpclett.0c01971, 10.1021/acsphyschemau.3c00031.
4) Lines 63-65: “To capture the signature of the CI, attosecond Raman spectroscopy has been theoretically proposed to detect the transient electronic coherence of wave packet in the vicinity of the CI [27–29].” TRUE-CARS is an additional approach able to reveal the passage of vibronic coherence through CI, which has been proposed and should be cited here (10.1039/d0sc06328b).
5) Lines 84-85: “Qt and coupling Qc modes”. The symbols “Qt” and “Qc” should be defined at the first occurrence. To my understanding, the theoretical framework used here is the same as that of Ref. 26. This should be properly acknowledged, and any differences should be discussed.
6) Line 111: The electric field defined here is inconsistent: a vector appears in the left hand side of the equation, while a scalar is assumed in the RHS.
7) Lines 127-129: “We then set the energy gap between ground and first excited state e1 = 1000 cm-1 and the gap between first and second excited states e2 = 1000 cm-1” This is a rather unnatural choice for an electronic transition from the ground to an electronically excited level. In the introduction, the authors mentioned several systems absorbing in the visible spectral region (12500-25000 cm-1). The authors should comment on this. In my opinion, this value is dangerously close to other molecular parameters (vibrational frequencies and the vibronic coupling term) and hence it can potentially impact the results obtained. I strongly suggest considering a more reliable value for their numerical analysis.
8) The authors have analyzed the quantum yield efficiency as a function of the pulse temporal profile, by modelling the beam as the sum of three profiles and tuning their relative amplitudes, durations and the wavelengths. While they obtained interesting results, the manipulation of the beam seems rather impractical from an experimental point of view. In this respect, the pulse chirp can represent a convenient parameter to tune the beam temporal profile from an experimental point-of-view (see: 10.1016/0009-2614(96)01092-5, 10.1021/acs.jpclett.1c02209 and 10.1038/s41467-022-35099-3). Additionally, it may be easily included in the presented model. To increase the impact and the audience of the present work, the authors should mention the probe chirp as an effective means of tuning the pulse profile, supported by citations to appropriate references.
9) Generally, the presentation could be improved in several places, and I think the senior author(s) should read the paper closely and edit the wording where needed to clarify the manuscript and improve grammar and style. I don’t have time to do detailed editing for the authors, but they need to work on the way the language is used so that the article makes its points more clearly. Below I have reported some of the areas (limited to the first 100 lines) that need a serious restyling.
Minor points:
1) There may be some inconsistencies in Eq. 4 and 3; two spectral densities (“J(w)”) are introduced in Eq. 4, an appropriate labelling would be in order to distinguish them. In the second line of Eq. 4, I think that the symbol “d” should read “t” for consistency with Eq. 3.
2) Lines 5-6: “excited-state potential energy surfaces (PES)” should read “excited-state potential energy surfaces (PESs)”
3) Line 7: “manipulated by varying” or “varied by tuning” would be more appropriate than “modulated by varying” here.
4) Line 17: “the microscopic physical processes” should read “microscopic physical processes”.
5) Line 18-19: “The laser excitation could induce a transition of electronic wave packet from molecular ground to the excited states” should read “The laser excitation can induce a transition of the electronic wave packet from the molecular ground to one or multiple excited states”.
6) Lines 19-21: “The degeneracy of potential energy surfaces (PESs) in a configuration space of polyatomic molecules, it induces the strong nonadiabatic coupling between two PESs” should read “The degeneracy of potential energy surfaces (PESs) in the configuration space of polyatomic molecules induces strong nonadiabatic coupling between two PES”.
7) Lines 29-30: “Polli et al. employed the transient absorption spectrometer to study the timescale of ultrafast isomerization” should read “Polli et al. employed transient absorption spectroscopy to unravel the timescales of ultrafast isomerization”.
8) Lines 40-41: “The femtosecond stimulated Raman spectroscopy (FSRS) is…” should read “Femtosecond stimulated Raman spectroscopy (FSRS) is…”.
9) Lines 73-74: “We firstly numerically synthesize the laser pulse and employ them” should read “We firstly numerically select the laser pulses and employ them”.
10) Lines 75-77: “It allows us to unravel the detailed mechanism and discover the key factors of determining of quantum efficiency” Should read “It allows us to unravel the detailed mechanism and discover the key factors, determining the quantum efficiency”.
11) Line 84: “linearly couple” should read “linearly coupled”.
12) Line 91: “site energies”. “Site” here is unclear. What does it refer to?
13) Eq. 2: the symbols “j=t,c” should appear under the summation not as subscripts of the frequencies.
14) Lines 95-97: “The bath has been assumed to be consisted with an infinite number of harmonic oscillators, each linearly coupled to the coupling and tuning mode, respectively” should read: “The bath has been assumed to consist of an infinite number of harmonic oscillators, each linearly coupled to the coupling and tuning modes, respectively”.
15) Lines 103-105: A reference to the mentioned theory here would be in order.
16) Line 116: “The laser pulse act on the model at time t = 0 fs” looking at the definition reported in Eq. 5, the laser pulse acts at “t=\tau_n”.
Comments on the Quality of English Language
See above
Author Response
Thank you very much for your acknowledgment of our work and for your valuable suggestions, which have greatly enhanced the professionalism of our paper. The specific details of the revisions are outlined in the documents we have submitted.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for Authors
Authors must check the scientific English they use. For example, in line 23 they indicate radiation-less transition when those molecular transitions are usually referred to as non-radiative transitions. In case authors want to indicate something, they have to specify what. Other example appears in line 142, where the refer to 1000 cm-1 as the amplitude of the laser pulse. The frequency of the laser pulse, omega_n, is explained inline 114 but used in line 111, before Eq(5). The wavenumber k_n is not properly introduced in the text. Therefore the paper needs a careful revision before meeting the journal standards and avoid confusions.
From the point of view of the fundamental physics underlying in this manuscript, it is very important to comment that the physical process of CI is closely related to the non absorbing resonances found almost 50 years ago [Arimondo, E., and G. Orriols. "Nonabsorbing atomic coherences by coherent two-photon transitions in a three-level optical pumping." Nuovo Cimento Lettere 17 (1976): 333-338.] A proper reference of this process also known as population trapping is needed. In Figures 1, 2 and 4, it would be very helpful to indicate the real scale of Qc and Qt (the horizontal axes) in order to attract potential readers.
With all this in mind, the manuscript presents a description with potential interest. A discussion on the existence of such lasers would be very necessary for the readers. Also an indication of the wavelength corresponding to the selected wavenumbers is necessary.
Finally, there is a major problem that must be addressed by authors before recommending publication. If I understand correctly the manuscript -as I said it is confusing- authors use 1000 cm^-1 wavenumber, this corresponds to more than 30 fs laser period, therefore a line shape as the one indicated in Figure 3 has to be properly justified and explained. Figure 3 indicates structures of a few femtoseconds thus instead to plot the amplitude it is important to plot the field (with amplitude and phase) otherwise the relevance -or not- of the result can not be evaluated. Sub-shapes of 3 fs, as indicated in line 175, need pulses of high frequency. Please discuss this before resubmission.
Comments on the Quality of English Language
Authors must check the scientific English they use.
It is a problem of scientific terminology.
Author Response
Thank you very much for your acknowledgment of our work and for your valuable suggestions, which have greatly enhanced the professionalism of our paper. The specific details of the revisions are outlined in the documents we have submitted.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsI am satisfied with the responses to my comments. The manuscript can be published in current form.
Author Response
Thank you very much for your satisfaction with the revision comments. Your suggestions are crucial to this manuscript. I would like to express my sincere gratitude to you again and wish you a happy life.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors have addressed most of the comments raised and the manuscript has been sufficiently improved to warrant publication in Photonics. I just have a residual comment related to my previous point #7, here reported [Lines 127-129: “We then set the energy gap between ground and first excited state e1 = 1000 cm-1 and the gap between first and second excited states e2 = 1000 cm-1” This is a rather unnatural choice for an electronic transition from the ground to an electronically excited level. In the introduction, the authors mentioned several systems absorbing in the visible spectral region (12500-25000 cm-1). The authors should comment on this. In my opinion, this value is dangerously close to other molecular parameters (vibrational frequencies and the vibronic coupling term) and hence it can potentially impact the results obtained. I strongly suggest considering a more reliable value for their numerical analysis)].
Although the authors mention the use of the Rotating Wave Approximation (RWA), which does not directly address my concern, they add "We believe that the conclusion obtained from different pulse profile do not changed by the energy gap between ground and excited states. For this, we also calculated a case of population dynamics with realistic scale of energy gap". It is essential for such calculations to be included in the manuscript or in the Supplementary Information (SI). Furthermore, the manuscript should explicitly state that "the conclusions drawn from different pulse profiles remain consistent regardless of the energy gap between ground and excited states."
Author Response
Thank you very much for your satisfaction with the revision comments. I have provided explanations and explanations for your doubts in the attachment. Your suggestions are crucial to this manuscript. I would like to express my sincere gratitude to you again and wish you a happy life.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsAll questions raised have been satisfactorily answer, except one: the waveform (I prefer to cal this pulse profile, but this is not an issue). Authors consider 1000 wavenumbers, mention RWA (rotating Waver approx) and at the same time mention pulse profiles with a degree of detail of few fs )in Fig and in Fig 6). Authors must state clearly the range of laser frequencies they are considering. I understand that they have to be in the UV or VUV, and that such wavenumbers refer only to the Rabi(coupling) frequencies ???
This need a clear explanation before publication.
Author Response
Thank you very much for your satisfaction with the reply to the revision comments. I have provided explanations and explanations about your doubts in the attachment. Your professional advice is crucial to this manuscript. I would like to express my sincere gratitude to you again and wish you a happy life.
Author Response File: Author Response.pdf
