Steady states are invaluable in the study of dynamical systems. High-dimensional dynamical systems, due to separation of time scales, often evolve toward a lower dimensional manifold M. We introduce an approach to locate saddle points (and other fixed points) that utilizes gradient extremals on such a priori unknown (Riemannian) manifolds, defined by adaptively sampled point clouds, with local coordinates discovered on-the-fly through manifold learning. The technique, which efficiently biases the dynamical system along a curve (as opposed to exhaustively exploring the state space), requires knowledge of a single minimum and the ability to sample around an arbitrary point. We demonstrate the effectiveness of the technique on the Müller–Brown potential mapped onto an unknown surface (namely, a sphere). Previous work employed a similar algorithmic framework to find saddle points using Newton trajectories and gentlest ascent dynamics; we, therefore, also offer a brief comparison with these methods.

1.
A. D.
Bochevarov
,
E.
Harder
,
T. F.
Hughes
,
J. R.
Greenwood
,
D. A.
Braden
,
D. M.
Philipp
,
D.
Rinaldo
,
M. D.
Halls
,
J.
Zhang
, and
R. A.
Friesner
, “
Jaguar: A high-performance quantum chemistry software program with strengths in life and materials sciences
,”
Int. J. Quantum Chem.
113
,
2110
2142
(
2013
).
2.
B.
Leimkuhler
and
C.
Matthews
, Molecular Dynamics: With Deterministic and Stochastic Numerical Methods,” Interdisciplinary Applied Mathematics (Springer, 2015).
3.
A.
Laio
and
M.
Parrinello
, “
Escaping free-energy minima
,”
Proc. Natl. Acad. Sci. U.S.A.
99
,
12562
12566
(
2002
).
4.
E.
Darve
,
D.
Rodríguez-Gómez
, and
A.
Pohorille
, “
Adaptive biasing force method for scalar and vector free energy calculations
,”
J. Chem. Phys.
128
,
144120
(
2008
).
5.
E.
Chiavazzo
,
R.
Covino
,
R. R.
Coifman
,
C. W.
Gear
,
A. S.
Georgiou
,
G.
Hummer
, and
I. G.
Kevrekidis
, “
Intrinsic map dynamics exploration for uncharted effective free-energy landscapes
,”
Proc. Natl. Acad. Sci. U.S.A.
114
,
E5494
E5503
(
2017
).
6.
R.
Olender
and
R.
Elber
, “
Calculation of classical trajectories with a very large time step: Formalism and numerical examples
,”
J. Chem. Phys.
105
,
9299
9315
(
1996
).
7.
H.
Jónsson
,
G.
Mills
, and
K. W.
Jacobsen
, “Nudged elastic band method for finding minimum energy paths of transitions,” in Classical and Quantum Dynamics in Condensed Phase Simulations (World Scientific, 1998), pp. 385–404.
8.
W. E.
W. Ren
and
E.
Vanden-Eijnden
, “
String method for the study of rare events
,”
Phys. Rev. B
66
,
052301
(
2002
).
9.
W.
Quapp
,
M.
Hirsch
,
O.
Imig
, and
D.
Heidrich
, “
Searching for saddle points of potential energy surfaces by following a reduced gradient
,”
J. Comput. Chem.
19
,
1087
1100
(
1998
).
10.
M.
Hirsch
and
W.
Quapp
, “
Reaction pathways and convexity of the potential energy surface: Application of Newton trajectories
,”
J. Math. Chem.
36
,
307
340
(
2004
).
11.
W.
E
and
X.
Zhou
, “
The gentlest ascent dynamics
,”
Nonlinearity
24
,
1831
1842
(
2010
).
12.
G.
Henkelman
and
H.
Jónsson
, “
A dimer method for finding saddle points on high dimensional potential surfaces using only first derivatives
,”
J. Chem. Phys.
111
,
7010
(
1999
).
13.
M.
Basilevsky
, “
The topography of potential energy surfaces
,”
Chem. Phys.
67
,
337
346
(
1982
).
14.
D. J.
Rowe
and
A.
Ryman
, “
Valleys and fall lines on a Riemannian manifold
,”
J. Math. Phys.
23
,
732
735
(
1982
).
15.
I.
Filippidis
and
K. J.
Kyriakopoulos
, “Roadmaps using gradient extremal paths,” in 2013 IEEE International Conference on Robotics and Automation (IEEE, 2013), pp. 370–375.
16.
R. R.
Coifman
and
S.
Lafon
, “
Diffusion maps
,”
Appl. Comput. Harmon. Anal.
21
,
5
30
(
2006
).
17.
J. M.
Bello-Rivas
,
A.
Georgiou
,
J.
Guckenheimer
, and
I. G.
Kevrekidis
, “
Staying the course: Iteratively locating equilibria of dynamical systems on Riemannian manifolds defined by point-clouds
,”
J. Math. Chem.
61
,
600
629
(
2023
).
18.
J. M.
Bello-Rivas
,
A.
Georgiou
,
H.
Vandecasteele
, and
I. G.
Kevrekidis
, “
Gentlest ascent dynamics on manifolds defined by adaptively sampled point-clouds
,”
J. Phys. Chem. B
127
,
5178
5189
(
2023
).
19.
A.
Lucia
and
Y.
Feng
, “
Global terrain methods
,”
Comput. Chem. Eng.
26
,
529
546
(
2002
).
20.
D. K.
Hoffman
,
R. S.
Nord
, and
K.
Ruedenberg
, “
Gradient extremals
,”
Theor. Chim. Acta
69
,
265
279
(
1986
).
21.
W.
Quapp
, “
Gradient extremals and valley floor bifurcations on potential energy surfaces
,”
Theor. Chim. Acta
75
,
447
460
(
1989
).
22.
E. L.
Allgower
and
K.
Georg
,
Introduction to Numerical Continuation Methods
(
Society for Industrial and Applied Mathematics
,
2003
).
23.
A.
Lucia
,
P. A.
Dimaggio
, and
P.
Depa
, “
A geometric terrain methodology for global optimization
,”
J. Glob. Optim.
29
,
297
314
(
2004
).
24.
M.
Hirsch
and
W.
Quapp
, “
The reaction pathway of a potential energy surface as curve with induced tangent
,”
Chem. Phys. Lett.
395
,
150
156
(
2004
).
25.
K.
Ohno
and
S.
Maeda
, “
A scaled hypersphere search method for the topography of reaction pathways on the potential energy surface
,”
Chem. Phys. Lett.
384
,
277
282
(
2004
).
26.
A.
Uppal
,
W.
Ray
, and
A.
Poore
, “
On the dynamic behavior of continuous stirred tank reactors
,”
Chem. Eng. Sci.
29
,
967
985
(
1974
).
27.
G.
Torrie
and
J.
Valleau
, “
Nonphysical sampling distributions in Monte Carlo free-energy estimation: Umbrella sampling
,”
J. Comput. Phys.
23
,
187
199
(
1977
).
28.
M. L. K.
Giacomo Fiorin
and
J.
Hénin
, “
Using collective variables to drive molecular dynamics simulations
,”
Mol. Phys.
111
,
3345
3362
(
2013
).
29.
A. L.
Ferguson
,
A. Z.
Panagiotopoulos
,
P. G.
Debenedetti
, and
I. G.
Kevrekidis
, “
Integrating diffusion maps with umbrella sampling: Application to alanine dipeptide
,”
J. Chem. Phys.
134
,
135103
(
2011
).
30.
C. E.
Rasmussen
and
C. K. I.
Williams
, “Gaussian processes for machine learning,” in Adaptive Computation and Machine Learning (MIT Press, 2006), pp. I–XVIII, 1–248.
31.
J. M.
Bofill
and
W.
Quapp
, “
Calculus of variations as a basic tool for modelling of reaction paths and localisation of stationary points on potential energy surfaces
,”
Mol. Phys.
118
,
e1667035
(
2020
).
32.
D.
Heidrich
, “
An introduction to the nomenclature and usage of the reaction path concept
,” in
The Reaction Path in Chemistry: Current Approaches and Perspectives
, edited by
D.
Heidrich
(
Kluwer Academic Publishers
,
1995
).
33.
A.
Behn
,
P. M.
Zimmerman
,
A. T.
Bell
, and
M.
Head-Gordon
, “
Incorporating linear synchronous transit interpolation into the growing string method: Algorithm and applications
,”
J. Chem. Theory Comput.
7
,
4019
4025
(
2011
).
34.
H.
Chaffey-Millar
,
A.
Nikodem
,
A. V.
Matveev
,
S.
Krüger
, and
N.
Rösch
, “
Improving upon string methods for transition state discovery
,”
J. Chem. Theory Comput.
8
,
777
786
(
2012
).
35.
D.
Sheppard
and
G.
Henkelman
, “
Paths to which the nudged elastic band converges
,”
J. Comput. Chem.
32
,
1769
1771
(
2011
).
36.
J. D.
Dunitz
, “
Chemical reaction paths
,”
Phil. Trans. R. Soc. Lond. B
272
,
99
108
(
1975
).
37.
J. M.
Bofill
,
W.
Quapp
, and
M.
Caballero
, “
The variational structure of gradient extremals
,”
J. Chem. Theory Comput.
8
,
927
935
(
2012
).
38.
J. M.
Bofill
and
W.
Quapp
, “
The variational nature of the gentlest ascent dynamics and the relation of a variational minimum of a curve and the minimum energy path
,”
Theor. Chem. Acc.
135
,
11
(
2015
).
39.
M. C.
Palenik
, “
Initial estimate for minimum energy pathways and transition states using velocities in internal coordinates
,”
Chem. Phys.
542
,
111046
(
2021
).
40.
T. A.
Halgren
and
W. N.
Lipscomb
, “
The synchronous-transit method for determining reaction pathways and locating molecular transition states
,”
Chem. Phys. Lett.
49
,
225
232
(
1977
).
41.
W.
Quapp
and
J. M.
Bofill
, “
Reaction rates in a theory of mechanochemical pathways
,”
J. Comput. Chem.
37
,
2467
2478
(
2016
).
42.
W.
Quapp
and
J. M.
Bofill
, “
A contribution to a theory of mechanochemical pathways by means of Newton trajectories
,”
Theor. Chem. Acc.
135
,
113
(
2016
).
43.
W.
Quapp
, “
Reduced gradient methods and their relation to reaction paths
,”
J. Theor. Comput. Chem.
02
,
385
417
(
2003
).
44.
J. M.
Bofill
,
W.
Quapp
, and
M.
Caballero
, “
Locating transition states on potential energy surfaces by the gentlest ascent dynamics
,”
Chem. Phys. Lett.
583
,
203
208
(
2013
).
You do not currently have access to this content.