Unraveling anharmonic effects in the vibrational predissociation spectra of H5O2(+) and its deuterated analogues.
Unraveling anharmonic effects in the vibrational predissociation spectra of H5O2(+) and its deuterated analogues.
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揭示 H5O2( ) 及其氘代类似物振动预解离谱中的非简谐效应。
DOI：
10.1021/jp109999b
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
A. McCoy
中科院分区：
文献类型：
--
作者：
T. Guasco;Mark A. Johnson;A. McCoy
本文通过对H（5）O（2）（+）Zundel离子及其氘代同位素体振动光谱的测量和计算的比较，研究了它们的非谐耦合性质。这是在最近的一项研究之后，我们报告了H（5）O（2）（+）、D（5）O（2）（+）和D（4）HO（2）（+）在10600至4000 cm（-1）之间的光谱，以及H（4）DO（2）（+）在OH和OD伸缩区域的光谱[J. Phys. Chem. B 2008，112，321 ]。虽然与外部OH和OD运动的基本原理相关联的较高能量跃迁的分配相对简单，但在分配涉及桥接质子的位移的较低频率区域时会出现困难，特别是对于同位素混合物种。在此，我们重新回顾了Ar标记的同位素异构体，并首次报道了H（4）DO（2）（+）的低能作用光谱，以及D（4）HO（2）（+）和D（5）O（2）（+）系统的显着改进的光谱。在几种情况下，使用红外-红外烧孔澄清频带分配。然后，我们调查的物理起源的非谐效应编码在这些光谱中使用最近开发的技术，其中的非谐频率和强度的过渡（涉及多达两个量子的激发）进行评估，使用基态概率振幅[J.物理.化学. A 2009年，113，7346 ]从扩散蒙特卡罗模拟。这种方法的优点是，它适用于低对称性系统[如（HDO）H（+）（OH（2））]，这些系统不容易使用高度精确的方法，如多构型时间相关Hartree（MCTDH）方法进行处理。此外，它自然地容纳了一个直观的评价类型的运动，有助于振子强度在各个区域的频谱，即使波函数本质上是不可分离的低维近似解的产品。H（5）O（2）（+）、D（5）O（2）（+）、H（4）DO（2）（+）和D（4）HO（2）（+）的光谱与这些物质的测量光谱非常吻合，从而重新解释了D（4）HO（2）（+）分子内弯曲区的两个谱带。
The nature of anharmonic couplings in the H(5)O(2)(+) "Zundel" ion and its deuterated isotopologues is investigated through comparison of their measured and calculated vibrational spectra. This follows a recent study in which we reported spectra for H(5)O(2)(+), D(5)O(2)(+), and D(4)HO(2)(+) from ∼600 to 4000 cm(-1), as well as H(4)DO(2)(+) in the OH and OD stretching regions [ J. Phys. Chem. B 2008 , 112 , 321 ]. While the assignments of the higher-energy transitions associated with the fundamentals of the exterior OH and OD motions are relatively straightforward, difficulties arise in the assignment of the lower-frequency regions that involve displacement of the bridging proton, especially for the isotopically mixed species. Here we revisit the Ar-tagged isotopomers, and report the low energy action spectrum of H(4)DO(2)(+) for the first time, as well as present significantly improved spectra for the D(4)HO(2)(+) and D(5)O(2)(+) systems. Band assignments are clarified in several cases using IR-IR hole-burning. We then investigate the physical origin of the anharmonic effects encoded in these spectra using a recently developed technique in which the anharmonic frequencies and intensities of transitions (involving up to two quanta of excitation) are evaluated using the ground state probability amplitudes [ J. Phys. Chem. A 2009 , 113 , 7346 ] obtained from diffusion Monte Carlo simulations. This approach has the advantage that it is applicable to low-symmetry systems [such as (HDO)H(+)(OH(2))] that are not readily addressed using highly accurate methods such as the multiconfigurational time-dependent Hartree (MCTDH) approach. Moreover, it naturally accommodates an intuitive evaluation of the types of motion that contribute oscillator strength in the various regions of the spectrum, even when the wave function is intrinsically not separable as a product of low-dimensional approximate solutions. Spectra for H(5)O(2)(+), D(5)O(2)(+), H(4)DO(2)(+), and D(4)HO(2)(+) that are calculated by this approach are shown to be in excellent agreement with the measured spectra for these species, leading to reassignments of two of the bands in the intramolecular bending region of D(4)HO(2)(+).
影响因子：
16.6
作者：
Baer, Marcel;Marx, Dominik;Mathias, Gerald
通讯作者：
Mathias, Gerald